diff --git a/src/core/all-units.h b/src/core/all-units.h
index fad814bf20..cb2563d2c8 100644
--- a/src/core/all-units.h
+++ b/src/core/all-units.h
@@ -5,6 +5,7 @@
 
 #include "automount.h"
 #include "device.h"
+#include "mount.h"
 #include "path.h"
 #include "scope.h"
 #include "service.h"
diff --git a/src/core/automount.c b/src/core/automount.c
index b4611981f2..ef5db87a7e 100644
--- a/src/core/automount.c
+++ b/src/core/automount.c
@@ -22,6 +22,7 @@
 #include "io-util.h"
 #include "label-util.h"
 #include "mkdir-label.h"
+#include "manager.h"
 #include "mount-util.h"
 #include "mount.h"
 #include "mountpoint-util.h"
diff --git a/src/core/automount.h b/src/core/automount.h
index e413f237ca..6f2ca7657b 100644
--- a/src/core/automount.h
+++ b/src/core/automount.h
@@ -1,8 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct Automount Automount;
-
 #include "unit.h"
 
 typedef enum AutomountResult {
@@ -15,7 +13,7 @@ typedef enum AutomountResult {
         _AUTOMOUNT_RESULT_INVALID = -EINVAL,
 } AutomountResult;
 
-struct Automount {
+typedef struct Automount {
         Unit meta;
 
         AutomountState state, deserialized_state;
@@ -35,7 +33,7 @@ struct Automount {
         sd_event_source *expire_event_source;
 
         AutomountResult result;
-};
+} Automount;
 
 extern const UnitVTable automount_vtable;
 
diff --git a/src/core/bpf-firewall.c b/src/core/bpf-firewall.c
index 69000c1389..85fce6f32a 100644
--- a/src/core/bpf-firewall.c
+++ b/src/core/bpf-firewall.c
@@ -20,6 +20,7 @@
 #include "bpf-program.h"
 #include "fd-util.h"
 #include "in-addr-prefix-util.h"
+#include "manager.h"
 #include "memory-util.h"
 #include "missing_syscall.h"
 #include "unit.h"
diff --git a/src/core/bpf-restrict-ifaces.c b/src/core/bpf-restrict-ifaces.c
index af49abd677..a9066ee2a9 100644
--- a/src/core/bpf-restrict-ifaces.c
+++ b/src/core/bpf-restrict-ifaces.c
@@ -3,6 +3,7 @@
 #include "fd-util.h"
 #include "bpf-restrict-ifaces.h"
 #include "netlink-util.h"
+#include "unit.h"
 
 #if BPF_FRAMEWORK
 /* libbpf, clang and llc compile time dependencies are satisfied */
diff --git a/src/core/bpf-restrict-ifaces.h b/src/core/bpf-restrict-ifaces.h
index 28f74279f5..80af1f3e5b 100644
--- a/src/core/bpf-restrict-ifaces.h
+++ b/src/core/bpf-restrict-ifaces.h
@@ -2,7 +2,6 @@
 #pragma once
 
 #include "fdset.h"
-#include "unit.h"
 
 typedef struct Unit Unit;
 
diff --git a/src/core/bpf-socket-bind.c b/src/core/bpf-socket-bind.c
index 8853f3eecc..437b084392 100644
--- a/src/core/bpf-socket-bind.c
+++ b/src/core/bpf-socket-bind.c
@@ -6,6 +6,7 @@
 
 #include "fd-util.h"
 #include "bpf-socket-bind.h"
+#include "unit.h"
 
 #if BPF_FRAMEWORK
 /* libbpf, clang, llvm and bpftool compile time dependencies are satisfied */
diff --git a/src/core/bpf-socket-bind.h b/src/core/bpf-socket-bind.h
index 28b25f6872..13a0fc1521 100644
--- a/src/core/bpf-socket-bind.h
+++ b/src/core/bpf-socket-bind.h
@@ -2,7 +2,8 @@
 #pragma once
 
 #include "fdset.h"
-#include "unit.h"
+
+typedef struct Unit Unit;
 
 int bpf_socket_bind_supported(void);
 
diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 7e4f7efa5e..27d81b0b85 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -27,6 +27,7 @@
 #include "io-util.h"
 #include "ip-protocol-list.h"
 #include "limits-util.h"
+#include "manager.h"
 #include "nulstr-util.h"
 #include "parse-util.h"
 #include "path-util.h"
diff --git a/src/core/core-varlink.c b/src/core/core-varlink.c
index c5735d0eaa..0dee43c01b 100644
--- a/src/core/core-varlink.c
+++ b/src/core/core-varlink.c
@@ -3,9 +3,12 @@
 #include "sd-varlink.h"
 
 #include "core-varlink.h"
+#include "dynamic-user.h"
 #include "json-util.h"
+#include "manager.h"
 #include "mkdir-label.h"
 #include "strv.h"
+#include "unit.h"
 #include "user-util.h"
 #include "varlink-internal.h"
 #include "varlink-io.systemd.UserDatabase.h"
diff --git a/src/core/core-varlink.h b/src/core/core-varlink.h
index 4b77620028..e4996f01ad 100644
--- a/src/core/core-varlink.h
+++ b/src/core/core-varlink.h
@@ -1,7 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "manager.h"
+typedef struct Manager Manager;
+typedef struct Unit Unit;
 
 int manager_setup_varlink_server(Manager *m);
 
diff --git a/src/core/dbus-cgroup.c b/src/core/dbus-cgroup.c
index 882c916c10..09692a93ec 100644
--- a/src/core/dbus-cgroup.c
+++ b/src/core/dbus-cgroup.c
@@ -22,6 +22,7 @@
 #include "in-addr-prefix-util.h"
 #include "ip-protocol-list.h"
 #include "limits-util.h"
+#include "manager.h"
 #include "memstream-util.h"
 #include "parse-util.h"
 #include "path-util.h"
diff --git a/src/core/dbus-execute.h b/src/core/dbus-execute.h
index 4b7cb86d3e..4ad7dd27a9 100644
--- a/src/core/dbus-execute.h
+++ b/src/core/dbus-execute.h
@@ -5,6 +5,7 @@
 #include "sd-bus-vtable.h"
 
 #include "execute.h"
+#include "unit.h"
 
 #define BUS_EXEC_STATUS_VTABLE(prefix, offset, flags)                   \
         BUS_PROPERTY_DUAL_TIMESTAMP(prefix "StartTimestamp", (offset) + offsetof(ExecStatus, start_timestamp), flags), \
diff --git a/src/core/dbus-job.h b/src/core/dbus-job.h
index 6f005811cb..50957303de 100644
--- a/src/core/dbus-job.h
+++ b/src/core/dbus-job.h
@@ -3,9 +3,10 @@
 
 #include "sd-bus.h"
 
-#include "unit.h"
 #include "bus-object.h"
 
+typedef struct Job Job;
+
 extern const sd_bus_vtable bus_job_vtable[];
 extern const BusObjectImplementation job_object;
 
diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c
index 6320e267a1..903f45d102 100644
--- a/src/core/dbus-manager.c
+++ b/src/core/dbus-manager.c
@@ -25,6 +25,7 @@
 #include "dbus-unit.h"
 #include "dbus-util.h"
 #include "dbus.h"
+#include "dynamic-user.h"
 #include "env-util.h"
 #include "fd-util.h"
 #include "fileio.h"
diff --git a/src/core/dbus-manager.h b/src/core/dbus-manager.h
index 9b050801a7..fcabca57c9 100644
--- a/src/core/dbus-manager.h
+++ b/src/core/dbus-manager.h
@@ -3,7 +3,9 @@
 
 #include "sd-bus-vtable.h"
 
-#include "manager.h"
+#include "time-util.h"
+
+typedef struct Manager Manager;
 
 extern const sd_bus_vtable bus_manager_vtable[];
 extern const sd_bus_vtable bus_manager_log_control_vtable[];
diff --git a/src/core/dbus-scope.h b/src/core/dbus-scope.h
index 8f1bc02e31..fb7467a0f5 100644
--- a/src/core/dbus-scope.h
+++ b/src/core/dbus-scope.h
@@ -4,9 +4,10 @@
 #include "sd-bus.h"
 #include "sd-bus-vtable.h"
 
-#include "scope.h"
 #include "unit.h"
 
+typedef struct Scope Scope;
+
 extern const sd_bus_vtable bus_scope_vtable[];
 
 int bus_scope_set_property(Unit *u, const char *name, sd_bus_message *i, UnitWriteFlags flags, sd_bus_error *error);
diff --git a/src/core/dbus-util.c b/src/core/dbus-util.c
index b44afc4258..e1a4cf0bdc 100644
--- a/src/core/dbus-util.c
+++ b/src/core/dbus-util.c
@@ -4,6 +4,7 @@
 #include "bus-util.h"
 #include "dbus-util.h"
 #include "escape.h"
+#include "manager.h"
 #include "parse-util.h"
 #include "path-util.h"
 #include "reboot-util.h"
diff --git a/src/core/dbus.h b/src/core/dbus.h
index bfd4c8ea4e..a362a652af 100644
--- a/src/core/dbus.h
+++ b/src/core/dbus.h
@@ -3,7 +3,9 @@
 
 #include "sd-bus.h"
 
-#include "manager.h"
+#include "fdset.h"
+
+typedef struct Manager Manager;
 
 void bus_send_pending_reload_message(Manager *m);
 
diff --git a/src/core/device.c b/src/core/device.c
index b6cdee73d4..08235caa42 100644
--- a/src/core/device.c
+++ b/src/core/device.c
@@ -13,6 +13,7 @@
 #include "device-util.h"
 #include "device.h"
 #include "log.h"
+#include "manager.h"
 #include "parse-util.h"
 #include "path-util.h"
 #include "ratelimit.h"
diff --git a/src/core/device.h b/src/core/device.h
index 631f45d45e..6f42cfa93a 100644
--- a/src/core/device.h
+++ b/src/core/device.h
@@ -3,8 +3,6 @@
 
 #include "unit.h"
 
-typedef struct Device Device;
-
 /* A mask specifying where we have seen the device currently. This is a bitmask because the device might show up
  * asynchronously from each other at various places. For example, in very common case a device might already be mounted
  * before udev finished probing it (think: a script setting up a loopback block device, formatting it and mounting it
@@ -17,7 +15,7 @@ typedef enum DeviceFound {
         _DEVICE_FOUND_MASK = DEVICE_FOUND_UDEV|DEVICE_FOUND_MOUNT|DEVICE_FOUND_SWAP,
 } DeviceFound;
 
-struct Device {
+typedef struct Device {
         Unit meta;
 
         char *sysfs, *deserialized_sysfs;
@@ -36,7 +34,7 @@ struct Device {
 
         /* The SYSTEMD_WANTS udev property for this device the last time we saw it */
         char **wants_property;
-};
+} Device;
 
 extern const UnitVTable device_vtable;
 
diff --git a/src/core/dynamic-user.c b/src/core/dynamic-user.c
index acfa1f52af..d21c709de7 100644
--- a/src/core/dynamic-user.c
+++ b/src/core/dynamic-user.c
@@ -12,6 +12,7 @@
 #include "fs-util.h"
 #include "iovec-util.h"
 #include "lock-util.h"
+#include "manager.h"
 #include "parse-util.h"
 #include "random-util.h"
 #include "serialize.h"
diff --git a/src/core/dynamic-user.h b/src/core/dynamic-user.h
index 303a7d081c..594595038d 100644
--- a/src/core/dynamic-user.h
+++ b/src/core/dynamic-user.h
@@ -1,7 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include <stdio.h>
+#include <stdbool.h>
+#include <sys/types.h>
+
+#include "fdset.h"
+#include "memory-util.h"
+
 typedef struct DynamicUser DynamicUser;
+typedef struct Manager Manager;
 
 typedef struct DynamicCreds {
         /* A combination of a dynamic user and group */
@@ -9,8 +17,6 @@ typedef struct DynamicCreds {
         DynamicUser *group;
 } DynamicCreds;
 
-#include "manager.h"
-
 /* Note that this object always allocates a pair of user and group under the same name, even if one of them isn't
  * used. This means, if you want to allocate a group and user pair, and they might have two different names, then you
  * need to allocated two of these objects. DynamicCreds below makes that easy. */
diff --git a/src/core/emergency-action.c b/src/core/emergency-action.c
index 2d756b306c..6752926bd9 100644
--- a/src/core/emergency-action.c
+++ b/src/core/emergency-action.c
@@ -6,6 +6,7 @@
 #include "bus-error.h"
 #include "bus-util.h"
 #include "emergency-action.h"
+#include "manager.h"
 #include "raw-reboot.h"
 #include "reboot-util.h"
 #include "special.h"
diff --git a/src/core/emergency-action.h b/src/core/emergency-action.h
index 5f7b0b4bc9..d0f1898a60 100644
--- a/src/core/emergency-action.h
+++ b/src/core/emergency-action.h
@@ -3,8 +3,11 @@
 
 #include <errno.h>
 
+#include "macro.h"
 #include "runtime-scope.h"
 
+typedef struct Manager Manager;
+
 typedef enum EmergencyAction {
         EMERGENCY_ACTION_NONE,
         EMERGENCY_ACTION_EXIT,
@@ -34,9 +37,6 @@ typedef enum EmergencyActionFlags {
         _EMERGENCY_ACTION_FLAGS_MAX  = (1 << 3) - 1,
 } EmergencyActionFlags;
 
-#include "macro.h"
-#include "manager.h"
-
 void emergency_action(
                 Manager *m,
                 EmergencyAction action,
diff --git a/src/core/exec-invoke.c b/src/core/exec-invoke.c
index f22aad76d2..fcbd62744b 100644
--- a/src/core/exec-invoke.c
+++ b/src/core/exec-invoke.c
@@ -24,11 +24,13 @@
 #include "bpf-restrict-fs.h"
 #include "btrfs-util.h"
 #include "capability-util.h"
+#include "cgroup.h"
 #include "cgroup-setup.h"
 #include "chase.h"
 #include "chattr-util.h"
 #include "chown-recursive.h"
 #include "copy.h"
+#include "dynamic-user.h"
 #include "env-util.h"
 #include "escape.h"
 #include "exec-credential.h"
@@ -43,10 +45,12 @@
 #include "ioprio-util.h"
 #include "iovec-util.h"
 #include "journal-send.h"
+#include "manager.h"
 #include "memfd-util.h"
 #include "missing_sched.h"
 #include "missing_syscall.h"
 #include "mkdir-label.h"
+#include "mount-util.h"
 #include "osc-context.h"
 #include "proc-cmdline.h"
 #include "process-util.h"
diff --git a/src/core/execute-serialize.c b/src/core/execute-serialize.c
index 380d6fa6bb..0aea6fe804 100644
--- a/src/core/execute-serialize.c
+++ b/src/core/execute-serialize.c
@@ -2,7 +2,9 @@
 
 #include "af-list.h"
 #include "capability-util.h"
+#include "cgroup.h"
 #include "cgroup-setup.h"
+#include "dynamic-user.h"
 #include "escape.h"
 #include "exec-credential.h"
 #include "execute-serialize.h"
diff --git a/src/core/execute.c b/src/core/execute.c
index 76ad7345ca..4aef0ad819 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -25,6 +25,7 @@
 #include "cgroup-setup.h"
 #include "constants.h"
 #include "cpu-set-util.h"
+#include "dynamic-user.h"
 #include "env-file.h"
 #include "env-util.h"
 #include "errno-list.h"
diff --git a/src/core/execute.h b/src/core/execute.h
index 63d5b448de..9b449012b2 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -1,19 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct ExecStatus ExecStatus;
-typedef struct ExecCommand ExecCommand;
-typedef struct ExecContext ExecContext;
-typedef struct ExecSharedRuntime ExecSharedRuntime;
-typedef struct DynamicCreds DynamicCreds;
-typedef struct ExecRuntime ExecRuntime;
-typedef struct ExecParameters ExecParameters;
-typedef struct Manager Manager;
-
 #include <sched.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <sys/capability.h>
+#include <sys/socket.h>
 
 #include "bus-unit-util.h"
 #include "cgroup-util.h"
@@ -22,6 +14,7 @@ typedef struct Manager Manager;
 #include "exec-util.h"
 #include "fdset.h"
 #include "list.h"
+#include "log-context.h"
 #include "namespace.h"
 #include "nsflags.h"
 #include "numa-util.h"
@@ -34,6 +27,17 @@ typedef struct Manager Manager;
 #include "set.h"
 #include "time-util.h"
 
+typedef struct CGroupContext CGroupContext;
+typedef struct ExecStatus ExecStatus;
+typedef struct ExecCommand ExecCommand;
+typedef struct ExecContext ExecContext;
+typedef struct ExecSharedRuntime ExecSharedRuntime;
+typedef struct DynamicCreds DynamicCreds;
+typedef struct ExecRuntime ExecRuntime;
+typedef struct ExecParameters ExecParameters;
+typedef struct Manager Manager;
+typedef struct Unit Unit;
+
 #define EXEC_STDIN_DATA_MAX (64U*1024U*1024U)
 
 typedef enum ExecUtmpMode {
@@ -494,9 +498,6 @@ struct ExecParameters {
                 .pidref_transport_fd    = -EBADF, \
         }
 
-#include "unit.h"
-#include "dynamic-user.h"
-
 int exec_spawn(
                 Unit *unit,
                 ExecCommand *command,
diff --git a/src/core/executor.c b/src/core/executor.c
index bc3566a9fc..daee9ea955 100644
--- a/src/core/executor.c
+++ b/src/core/executor.c
@@ -9,6 +9,8 @@
 #include "argv-util.h"
 #include "build.h"
 #include "capability-util.h"
+#include "cgroup.h"
+#include "dynamic-user.h"
 #include "exec-invoke.h"
 #include "execute-serialize.h"
 #include "execute.h"
diff --git a/src/core/fuzz-execute-serialize.c b/src/core/fuzz-execute-serialize.c
index 05abee5a4e..67437549ea 100644
--- a/src/core/fuzz-execute-serialize.c
+++ b/src/core/fuzz-execute-serialize.c
@@ -20,6 +20,7 @@
 #include <stdio.h>
 
 #include "alloc-util.h"
+#include "dynamic-user.h"
 #include "execute-serialize.h"
 #include "fd-util.h"
 #include "fuzz.h"
diff --git a/src/core/fuzz-unit-file.c b/src/core/fuzz-unit-file.c
index 57480cf766..d8987c9648 100644
--- a/src/core/fuzz-unit-file.c
+++ b/src/core/fuzz-unit-file.c
@@ -5,6 +5,7 @@
 #include "fuzz.h"
 #include "install.h"
 #include "load-fragment.h"
+#include "manager.h"
 #include "manager-dump.h"
 #include "memstream-util.h"
 #include "string-util.h"
diff --git a/src/core/job.c b/src/core/job.c
index 4209a7c8d4..d051b3db6d 100644
--- a/src/core/job.c
+++ b/src/core/job.c
@@ -16,6 +16,7 @@
 #include "job.h"
 #include "log.h"
 #include "macro.h"
+#include "manager.h"
 #include "parse-util.h"
 #include "serialize.h"
 #include "set.h"
diff --git a/src/core/job.h b/src/core/job.h
index 388890e368..3c1e861bbc 100644
--- a/src/core/job.h
+++ b/src/core/job.h
@@ -7,6 +7,8 @@
 #include "sd-event.h"
 
 #include "list.h"
+#include "memory-util.h"
+#include "time-util.h"
 #include "unit-dependency-atom.h"
 
 typedef struct ActivationDetails ActivationDetails;
diff --git a/src/core/kill.h b/src/core/kill.h
index 3add663d71..97a295e1e5 100644
--- a/src/core/kill.h
+++ b/src/core/kill.h
@@ -1,8 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct KillContext KillContext;
-
 #include <stdbool.h>
 #include <stdio.h>
 
@@ -18,7 +16,7 @@ typedef enum KillMode {
         _KILL_MODE_INVALID = -EINVAL,
 } KillMode;
 
-struct KillContext {
+typedef struct KillContext {
         KillMode kill_mode;
         int kill_signal;
         int restart_kill_signal;
@@ -26,7 +24,7 @@ struct KillContext {
         int watchdog_signal;
         bool send_sigkill;
         bool send_sighup;
-};
+} KillContext;
 
 typedef enum KillWhom {
         /* Kill whom is a property of an operation */
diff --git a/src/core/load-dropin.c b/src/core/load-dropin.c
index 5c1ccc966f..0256f70635 100644
--- a/src/core/load-dropin.c
+++ b/src/core/load-dropin.c
@@ -1,16 +1,29 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include "conf-parser.h"
+#include "dropin.h"
 #include "fs-util.h"
 #include "load-dropin.h"
 #include "load-fragment.h"
 #include "log.h"
+#include "manager.h"
 #include "stat-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "unit-name.h"
 #include "unit.h"
 
+int unit_find_dropin_paths(Unit *u, bool use_unit_path_cache, char ***paths) {
+        assert(u);
+
+        return unit_file_find_dropin_paths(NULL,
+                                           u->manager->lookup_paths.search_path,
+                                           use_unit_path_cache ? u->manager->unit_path_cache : NULL,
+                                           ".d", ".conf",
+                                           u->id, u->aliases,
+                                           paths);
+}
+
 static int process_deps(Unit *u, UnitDependency dependency, const char *dir_suffix) {
         _cleanup_strv_free_ char **paths = NULL;
         int r;
diff --git a/src/core/load-dropin.h b/src/core/load-dropin.h
index 141bc7dd0f..864ea4f083 100644
--- a/src/core/load-dropin.h
+++ b/src/core/load-dropin.h
@@ -1,20 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "dropin.h"
-#include "unit.h"
+#include <stdbool.h>
+
+typedef struct Unit Unit;
 
 /* Read service data supplementary drop-in directories */
 
-static inline int unit_find_dropin_paths(Unit *u, bool use_unit_path_cache, char ***paths) {
-        assert(u);
-
-        return unit_file_find_dropin_paths(NULL,
-                                           u->manager->lookup_paths.search_path,
-                                           use_unit_path_cache ? u->manager->unit_path_cache : NULL,
-                                           ".d", ".conf",
-                                           u->id, u->aliases,
-                                           paths);
-}
+int unit_find_dropin_paths(Unit *u, bool use_unit_path_cache, char ***paths);
 
 int unit_load_dropin(Unit *u);
diff --git a/src/core/load-fragment.h b/src/core/load-fragment.h
index 0e68d1bb84..6aa8f479f5 100644
--- a/src/core/load-fragment.h
+++ b/src/core/load-fragment.h
@@ -2,7 +2,8 @@
 #pragma once
 
 #include "conf-parser.h"
-#include "unit.h"
+
+typedef struct Unit Unit;
 
 /* These functions are declared in the header to make them accessible to unit tests. */
 bool contains_instance_specifier_superset(const char *s);
diff --git a/src/core/manager-dump.c b/src/core/manager-dump.c
index 7e678fa03e..9cb184b4d2 100644
--- a/src/core/manager-dump.c
+++ b/src/core/manager-dump.c
@@ -4,6 +4,7 @@
 #include "fd-util.h"
 #include "fileio.h"
 #include "hashmap.h"
+#include "manager.h"
 #include "manager-dump.h"
 #include "memstream-util.h"
 #include "unit-serialize.h"
diff --git a/src/core/manager-dump.h b/src/core/manager-dump.h
index 5b96f26f54..a02c29ad68 100644
--- a/src/core/manager-dump.h
+++ b/src/core/manager-dump.h
@@ -3,7 +3,7 @@
 
 #include <stdio.h>
 
-#include "manager.h"
+typedef struct Manager Manager;
 
 void manager_dump_jobs(Manager *s, FILE *f, char **patterns, const char *prefix);
 int manager_get_dump_jobs_string(Manager *m, char **patterns, const char *prefix, char **ret);
diff --git a/src/core/manager-serialize.c b/src/core/manager-serialize.c
index c5cb82e8d5..ae4472b38b 100644
--- a/src/core/manager-serialize.c
+++ b/src/core/manager-serialize.c
@@ -5,6 +5,7 @@
 #include "clean-ipc.h"
 #include "core-varlink.h"
 #include "dbus.h"
+#include "dynamic-user.h"
 #include "fd-util.h"
 #include "fileio.h"
 #include "format-util.h"
diff --git a/src/core/manager-serialize.h b/src/core/manager-serialize.h
index c52261e378..7d4e8effb2 100644
--- a/src/core/manager-serialize.h
+++ b/src/core/manager-serialize.h
@@ -2,10 +2,12 @@
 #pragma once
 
 #include <stdbool.h>
+#include <stdio.h>
 
-#include "manager.h"
 #include "fdset.h"
 
+typedef struct Manager Manager;
+
 #define DESTROY_IPC_FLAG (UINT32_C(1) << 31)
 
 int manager_open_serialization(Manager *m, FILE **ret_f);
diff --git a/src/core/manager.c b/src/core/manager.c
index cf000d8f21..15c8f2b90d 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -42,6 +42,7 @@
 #include "dbus-unit.h"
 #include "dbus.h"
 #include "dirent-util.h"
+#include "dynamic-user.h"
 #include "env-util.h"
 #include "escape.h"
 #include "event-util.h"
@@ -5182,11 +5183,3 @@ static const char* const manager_timestamp_table[_MANAGER_TIMESTAMP_MAX] = {
 };
 
 DEFINE_STRING_TABLE_LOOKUP(manager_timestamp, ManagerTimestamp);
-
-static const char* const oom_policy_table[_OOM_POLICY_MAX] = {
-        [OOM_CONTINUE] = "continue",
-        [OOM_STOP]     = "stop",
-        [OOM_KILL]     = "kill",
-};
-
-DEFINE_STRING_TABLE_LOOKUP(oom_policy, OOMPolicy);
diff --git a/src/core/manager.h b/src/core/manager.h
index a07c665e5b..cbad223d1b 100644
--- a/src/core/manager.h
+++ b/src/core/manager.h
@@ -9,14 +9,22 @@
 #include "sd-event.h"
 #include "sd-varlink.h"
 
-#include "common-signal.h"
 #include "cgroup-util.h"
 #include "cgroup.h"
+#include "common-signal.h"
+#include "emergency-action.h"
+#include "execute.h"
 #include "fdset.h"
 #include "hashmap.h"
+#include "job.h"
 #include "list.h"
+#include "path-lookup.h"
 #include "prioq.h"
 #include "ratelimit.h"
+#include "show-status.h"
+#include "transaction.h"
+#include "unit-name.h"
+#include "unit.h"
 
 struct libmnt_monitor;
 typedef struct Unit Unit;
@@ -62,21 +70,6 @@ typedef enum ManagerObjective {
         _MANAGER_OBJECTIVE_INVALID = -EINVAL,
 } ManagerObjective;
 
-typedef enum StatusType {
-        STATUS_TYPE_EPHEMERAL,
-        STATUS_TYPE_NORMAL,
-        STATUS_TYPE_NOTICE,
-        STATUS_TYPE_EMERGENCY,
-} StatusType;
-
-typedef enum OOMPolicy {
-        OOM_CONTINUE,          /* The kernel or systemd-oomd kills the process it wants to kill, and that's it */
-        OOM_STOP,              /* The kernel or systemd-oomd kills the process it wants to kill, and we stop the unit */
-        OOM_KILL,              /* The kernel or systemd-oomd kills the process it wants to kill, and all others in the unit, and we stop the unit */
-        _OOM_POLICY_MAX,
-        _OOM_POLICY_INVALID = -EINVAL,
-} OOMPolicy;
-
 /* Notes:
  * 1. TIMESTAMP_FIRMWARE, TIMESTAMP_LOADER, TIMESTAMP_KERNEL, TIMESTAMP_INITRD,
  *    TIMESTAMP_SECURITY_START, and TIMESTAMP_SECURITY_FINISH are set only when
@@ -135,14 +128,6 @@ typedef enum WatchdogType {
         _WATCHDOG_TYPE_MAX,
 } WatchdogType;
 
-#include "execute.h"
-#include "job.h"
-#include "path-lookup.h"
-#include "show-status.h"
-#include "transaction.h"
-#include "unit-name.h"
-#include "unit.h"
-
 typedef enum ManagerTestRunFlags {
         MANAGER_TEST_NORMAL                  = 0,       /* run normally */
         MANAGER_TEST_RUN_MINIMAL             = 1 << 0,  /* create basic data structures */
@@ -670,9 +655,6 @@ LogTarget manager_get_executor_log_target(Manager *m);
 
 int manager_allocate_idle_pipe(Manager *m);
 
-const char* oom_policy_to_string(OOMPolicy i) _const_;
-OOMPolicy oom_policy_from_string(const char *s) _pure_;
-
 void unit_defaults_init(UnitDefaults *defaults, RuntimeScope scope);
 void unit_defaults_done(UnitDefaults *defaults);
 
diff --git a/src/core/mount.h b/src/core/mount.h
index 7fd643f6fa..c754ae7933 100644
--- a/src/core/mount.h
+++ b/src/core/mount.h
@@ -1,9 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct Mount Mount;
-
-#include "dynamic-user.h"
 #include "kill.h"
 #include "pidref.h"
 #include "unit.h"
@@ -42,7 +39,7 @@ typedef enum MountProcFlags {
         MOUNT_PROC_JUST_CHANGED = 1 << 2,
 } MountProcFlags;
 
-struct Mount {
+typedef struct Mount {
         Unit meta;
 
         char *where;
@@ -88,7 +85,7 @@ struct Mount {
         sd_event_source *timer_event_source;
 
         unsigned n_retry_umount;
-};
+} Mount;
 
 extern const UnitVTable mount_vtable;
 
diff --git a/src/core/path.c b/src/core/path.c
index 4556dbfc71..364d94f528 100644
--- a/src/core/path.c
+++ b/src/core/path.c
@@ -16,6 +16,7 @@
 #include "glob-util.h"
 #include "inotify-util.h"
 #include "macro.h"
+#include "manager.h"
 #include "mkdir-label.h"
 #include "path.h"
 #include "path-util.h"
diff --git a/src/core/path.h b/src/core/path.h
index cb5b662911..8a3b8b3592 100644
--- a/src/core/path.h
+++ b/src/core/path.h
@@ -1,10 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct Path Path;
-typedef struct PathSpec PathSpec;
-typedef struct ActivationDetailsPath ActivationDetailsPath;
-
 #include "unit.h"
 
 typedef enum PathType {
@@ -52,7 +48,7 @@ typedef enum PathResult {
         _PATH_RESULT_INVALID = -EINVAL,
 } PathResult;
 
-struct Path {
+typedef struct Path {
         Unit meta;
 
         LIST_HEAD(PathSpec, specs);
@@ -67,12 +63,12 @@ struct Path {
         RateLimit trigger_limit;
 
         sd_event_source *trigger_notify_event_source;
-};
+} Path;
 
-struct ActivationDetailsPath {
+typedef struct ActivationDetailsPath {
         ActivationDetails meta;
         char *trigger_path_filename;
-};
+} ActivationDetailsPath;
 
 void path_free_specs(Path *p);
 
diff --git a/src/core/scope.c b/src/core/scope.c
index 208716ea07..caeadd7e23 100644
--- a/src/core/scope.c
+++ b/src/core/scope.c
@@ -10,6 +10,7 @@
 #include "exit-status.h"
 #include "load-dropin.h"
 #include "log.h"
+#include "manager.h"
 #include "process-util.h"
 #include "random-util.h"
 #include "scope.h"
diff --git a/src/core/scope.h b/src/core/scope.h
index 1090431c13..27f2c83b23 100644
--- a/src/core/scope.h
+++ b/src/core/scope.h
@@ -1,8 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct Scope Scope;
-
 #include "cgroup.h"
 #include "kill.h"
 #include "unit.h"
@@ -16,7 +14,7 @@ typedef enum ScopeResult {
         _SCOPE_RESULT_INVALID = -EINVAL,
 } ScopeResult;
 
-struct Scope {
+typedef struct Scope {
         Unit meta;
 
         CGroupContext cgroup_context;
@@ -41,7 +39,7 @@ struct Scope {
         char *group;
 
         OOMPolicy oom_policy;
-};
+} Scope;
 
 extern const UnitVTable scope_vtable;
 
diff --git a/src/core/service.h b/src/core/service.h
index 68be9075c1..a542c0fb11 100644
--- a/src/core/service.h
+++ b/src/core/service.h
@@ -1,12 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct Service Service;
-typedef struct ServiceFDStore ServiceFDStore;
-typedef struct ServiceExtraFD ServiceExtraFD;
-
 #include "exit-status.h"
 #include "kill.h"
+#include "manager.h"
 #include "open-file.h"
 #include "path.h"
 #include "pidref.h"
@@ -14,6 +11,8 @@ typedef struct ServiceExtraFD ServiceExtraFD;
 #include "socket.h"
 #include "unit.h"
 
+typedef struct Service Service;
+
 typedef enum ServiceRestart {
         SERVICE_RESTART_NO,
         SERVICE_RESTART_ON_SUCCESS,
@@ -101,7 +100,7 @@ typedef enum ServiceRestartMode {
         _SERVICE_RESTART_MODE_INVALID = -EINVAL,
 } ServiceRestartMode;
 
-struct ServiceFDStore {
+typedef struct ServiceFDStore {
         Service *service;
 
         int fd;
@@ -109,13 +108,13 @@ struct ServiceFDStore {
         sd_event_source *event_source;
         bool do_poll;
 
-        LIST_FIELDS(ServiceFDStore, fd_store);
-};
+        LIST_FIELDS(struct ServiceFDStore, fd_store);
+} ServiceFDStore;
 
-struct ServiceExtraFD {
+typedef struct ServiceExtraFD {
         int fd;
         char *fdname;
-};
+} ServiceExtraFD;
 
 struct Service {
         Unit meta;
diff --git a/src/core/slice.c b/src/core/slice.c
index ba6f2fb9c5..4a9ff98ee9 100644
--- a/src/core/slice.c
+++ b/src/core/slice.c
@@ -7,6 +7,7 @@
 #include "dbus-unit.h"
 #include "fd-util.h"
 #include "log.h"
+#include "manager.h"
 #include "serialize.h"
 #include "slice.h"
 #include "special.h"
diff --git a/src/core/slice.h b/src/core/slice.h
index 37e1f700f8..46faecc030 100644
--- a/src/core/slice.h
+++ b/src/core/slice.h
@@ -3,9 +3,7 @@
 
 #include "unit.h"
 
-typedef struct Slice Slice;
-
-struct Slice {
+typedef struct Slice {
         Unit meta;
 
         SliceState state, deserialized_state;
@@ -16,7 +14,7 @@ struct Slice {
         CGroupContext cgroup_context;
 
         CGroupRuntime *cgroup_runtime;
-};
+} Slice;
 
 extern const UnitVTable slice_vtable;
 
diff --git a/src/core/socket.c b/src/core/socket.c
index 861aaba3d4..bb1db8e90e 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -28,6 +28,7 @@
 #include "ip-protocol-list.h"
 #include "label-util.h"
 #include "log.h"
+#include "manager.h"
 #include "mkdir-label.h"
 #include "parse-util.h"
 #include "path-util.h"
diff --git a/src/core/socket.h b/src/core/socket.h
index 51fc96280b..240a9ac965 100644
--- a/src/core/socket.h
+++ b/src/core/socket.h
@@ -1,14 +1,13 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct Socket Socket;
-typedef struct SocketPeer SocketPeer;
-
-#include "mount.h"
 #include "pidref.h"
 #include "socket-util.h"
 #include "unit.h"
 
+typedef struct Socket Socket;
+typedef struct SocketPeer SocketPeer;
+
 typedef enum SocketExecCommand {
         SOCKET_EXEC_START_PRE,
         SOCKET_EXEC_START_CHOWN,
diff --git a/src/core/swap.c b/src/core/swap.c
index cc5a21ee78..a8549699ff 100644
--- a/src/core/swap.c
+++ b/src/core/swap.c
@@ -17,6 +17,7 @@
 #include "fd-util.h"
 #include "format-util.h"
 #include "fstab-util.h"
+#include "manager.h"
 #include "parse-util.h"
 #include "path-util.h"
 #include "process-util.h"
diff --git a/src/core/swap.h b/src/core/swap.h
index d9bbd377f0..fce7ea5e56 100644
--- a/src/core/swap.h
+++ b/src/core/swap.h
@@ -10,8 +10,6 @@
 #include "pidref.h"
 #include "unit.h"
 
-typedef struct Swap Swap;
-
 typedef enum SwapExecCommand {
         SWAP_EXEC_ACTIVATE,
         SWAP_EXEC_DEACTIVATE,
@@ -38,7 +36,7 @@ typedef struct SwapParameters {
         bool priority_set;
 } SwapParameters;
 
-struct Swap {
+typedef struct Swap {
         Unit meta;
 
         char *what;
@@ -85,7 +83,7 @@ struct Swap {
         devices for the same swap. We chain them up here. */
 
         LIST_FIELDS(struct Swap, same_devnode);
-};
+} Swap;
 
 extern const UnitVTable swap_vtable;
 
diff --git a/src/core/target.h b/src/core/target.h
index bb909d664f..9e7c77c027 100644
--- a/src/core/target.h
+++ b/src/core/target.h
@@ -3,13 +3,11 @@
 
 #include "unit.h"
 
-typedef struct Target Target;
-
-struct Target {
+typedef struct Target {
         Unit meta;
 
         TargetState state, deserialized_state;
-};
+} Target;
 
 extern const UnitVTable target_vtable;
 
diff --git a/src/core/timer.c b/src/core/timer.c
index b37a67f310..d69e229922 100644
--- a/src/core/timer.c
+++ b/src/core/timer.c
@@ -12,6 +12,7 @@
 #include "dbus-timer.h"
 #include "dbus-unit.h"
 #include "fs-util.h"
+#include "manager.h"
 #include "parse-util.h"
 #include "random-util.h"
 #include "serialize.h"
diff --git a/src/core/timer.h b/src/core/timer.h
index 14a9931dff..90f19a7cf4 100644
--- a/src/core/timer.h
+++ b/src/core/timer.h
@@ -1,9 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct Timer Timer;
-typedef struct ActivationDetailsTimer ActivationDetailsTimer;
-
 #include "calendarspec.h"
 #include "unit.h"
 
@@ -37,7 +34,7 @@ typedef enum TimerResult {
         _TIMER_RESULT_INVALID = -EINVAL,
 } TimerResult;
 
-struct Timer {
+typedef struct Timer {
         Unit meta;
 
         usec_t accuracy_usec;
@@ -64,12 +61,12 @@ struct Timer {
         bool defer_reactivation;
 
         char *stamp_path;
-};
+} Timer;
 
-struct ActivationDetailsTimer {
+typedef struct ActivationDetailsTimer {
         ActivationDetails meta;
         dual_timestamp last_trigger;
-};
+} ActivationDetailsTimer;
 
 #define TIMER_MONOTONIC_CLOCK(t) ((t)->wake_system ? CLOCK_BOOTTIME_ALARM : CLOCK_MONOTONIC)
 
diff --git a/src/core/transaction.c b/src/core/transaction.c
index 07fd612d91..6d0d7e73be 100644
--- a/src/core/transaction.c
+++ b/src/core/transaction.c
@@ -8,6 +8,7 @@
 #include "bus-common-errors.h"
 #include "bus-error.h"
 #include "dbus-unit.h"
+#include "manager.h"
 #include "slice.h"
 #include "strv.h"
 #include "terminal-util.h"
diff --git a/src/core/transaction.h b/src/core/transaction.h
index b6728a35d7..1f58fcebcc 100644
--- a/src/core/transaction.h
+++ b/src/core/transaction.h
@@ -1,20 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct Transaction Transaction;
-typedef enum TransactionAddFlags TransactionAddFlags;
-
 #include "hashmap.h"
 #include "job.h"
-#include "manager.h"
-#include "unit.h"
 
-struct Transaction {
+typedef struct Transaction {
         /* Jobs to be added */
         Hashmap *jobs;        /* Unit object => Job object list 1:1 */
         Job *anchor_job;      /* The job the user asked for */
         bool irreversible;
-};
+} Transaction;
 
 Transaction* transaction_new(bool irreversible);
 Transaction* transaction_free(Transaction *tr);
diff --git a/src/core/unit-printf.c b/src/core/unit-printf.c
index f25e2e3986..0bdacfc3c0 100644
--- a/src/core/unit-printf.c
+++ b/src/core/unit-printf.c
@@ -4,6 +4,7 @@
 #include "cgroup-util.h"
 #include "format-util.h"
 #include "macro.h"
+#include "manager.h"
 #include "sd-path.h"
 #include "specifier.h"
 #include "string-util.h"
diff --git a/src/core/unit-serialize.c b/src/core/unit-serialize.c
index 13aea615dd..a38b38590a 100644
--- a/src/core/unit-serialize.c
+++ b/src/core/unit-serialize.c
@@ -10,6 +10,7 @@
 #include "parse-util.h"
 #include "serialize.h"
 #include "string-table.h"
+#include "unit.h"
 #include "unit-serialize.h"
 #include "user-util.h"
 
diff --git a/src/core/unit-serialize.h b/src/core/unit-serialize.h
index ab8a8e3be9..a7ac03cf82 100644
--- a/src/core/unit-serialize.h
+++ b/src/core/unit-serialize.h
@@ -1,11 +1,13 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include <stdbool.h>
 #include <stdio.h>
 
-#include "unit.h"
 #include "fdset.h"
 
+typedef struct Unit Unit;
+
 /* These functions serialize state for our own usage, i.e.: across a reload/reexec, rather than for being
  * passed to a child process. */
 
diff --git a/src/core/unit.c b/src/core/unit.c
index c25777671d..db14297622 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -24,6 +24,7 @@
 #include "dbus-unit.h"
 #include "dbus.h"
 #include "dropin.h"
+#include "dynamic-user.h"
 #include "env-util.h"
 #include "escape.h"
 #include "exec-credential.h"
@@ -6810,6 +6811,14 @@ static const char* const unit_mount_dependency_type_table[_UNIT_MOUNT_DEPENDENCY
 
 DEFINE_STRING_TABLE_LOOKUP(unit_mount_dependency_type, UnitMountDependencyType);
 
+static const char* const oom_policy_table[_OOM_POLICY_MAX] = {
+        [OOM_CONTINUE] = "continue",
+        [OOM_STOP]     = "stop",
+        [OOM_KILL]     = "kill",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(oom_policy, OOMPolicy);
+
 UnitDependency unit_mount_dependency_type_to_dependency_type(UnitMountDependencyType t) {
         switch (t) {
 
diff --git a/src/core/unit.h b/src/core/unit.h
index 6a46cbda0a..5bf52f5f6d 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -9,7 +9,21 @@
 
 #include "sd-id128.h"
 
-/* Circular dependency with manager.h, needs to be defined before local includes */
+#include "cgroup.h"
+#include "condition.h"
+#include "emergency-action.h"
+#include "execute.h"
+#include "install.h"
+#include "job.h"
+#include "list.h"
+#include "log-context.h"
+#include "mount-util.h"
+#include "pidref.h"
+#include "ratelimit.h"
+#include "unit-file.h"
+
+typedef struct UnitRef UnitRef;
+
 typedef enum UnitMountDependencyType {
         UNIT_MOUNT_WANTS,
         UNIT_MOUNT_REQUIRES,
@@ -17,18 +31,6 @@ typedef enum UnitMountDependencyType {
         _UNIT_MOUNT_DEPENDENCY_TYPE_INVALID = -EINVAL,
 } UnitMountDependencyType;
 
-#include "cgroup.h"
-#include "condition.h"
-#include "emergency-action.h"
-#include "install.h"
-#include "list.h"
-#include "log-context.h"
-#include "mount-util.h"
-#include "pidref.h"
-#include "unit-file.h"
-
-typedef struct UnitRef UnitRef;
-
 typedef enum KillOperation {
         KILL_TERMINATE,
         KILL_TERMINATE_AND_LOG,
@@ -46,6 +48,21 @@ typedef enum CollectMode {
         _COLLECT_MODE_INVALID = -EINVAL,
 } CollectMode;
 
+typedef enum OOMPolicy {
+        OOM_CONTINUE,          /* The kernel or systemd-oomd kills the process it wants to kill, and that's it */
+        OOM_STOP,              /* The kernel or systemd-oomd kills the process it wants to kill, and we stop the unit */
+        OOM_KILL,              /* The kernel or systemd-oomd kills the process it wants to kill, and all others in the unit, and we stop the unit */
+        _OOM_POLICY_MAX,
+        _OOM_POLICY_INVALID = -EINVAL,
+} OOMPolicy;
+
+typedef enum StatusType {
+        STATUS_TYPE_EPHEMERAL,
+        STATUS_TYPE_NORMAL,
+        STATUS_TYPE_NOTICE,
+        STATUS_TYPE_EMERGENCY,
+} StatusType;
+
 static inline bool UNIT_IS_ACTIVE_OR_RELOADING(UnitActiveState t) {
         return IN_SET(t, UNIT_ACTIVE, UNIT_RELOADING, UNIT_REFRESHING);
 }
@@ -200,8 +217,6 @@ static inline void* UNIT_DEPENDENCY_TO_PTR(UnitDependency d) {
         return INT_TO_PTR(d);
 }
 
-#include "job.h"
-
 struct UnitRef {
         /* Keeps tracks of references to a unit. This is useful so
          * that we can merge two units if necessary and correct all
@@ -1061,6 +1076,9 @@ UnitMountDependencyType unit_mount_dependency_type_from_string(const char *s) _c
 const char* unit_mount_dependency_type_to_string(UnitMountDependencyType t) _const_;
 UnitDependency unit_mount_dependency_type_to_dependency_type(UnitMountDependencyType t) _pure_;
 
+const char* oom_policy_to_string(OOMPolicy i) _const_;
+OOMPolicy oom_policy_from_string(const char *s) _pure_;
+
 /* Macros which append UNIT= or USER_UNIT= to the message */
 
 #define log_unit_full_errno_zerook(unit, level, error, ...)             \