diff --git a/src/basic/proc-cmdline.h b/src/basic/proc-cmdline.h
index 42a8ef1eb9..6abf57ac3c 100644
--- a/src/basic/proc-cmdline.h
+++ b/src/basic/proc-cmdline.h
@@ -4,10 +4,15 @@
 #include "basic-forward.h"
 
 typedef enum ProcCmdlineFlags {
-        PROC_CMDLINE_STRIP_RD_PREFIX    = 1 << 0, /* automatically strip "rd." prefix if it is set (and we are in the initrd, since otherwise we'd not consider it anyway) */
-        PROC_CMDLINE_VALUE_OPTIONAL     = 1 << 1, /* the value is optional (for boolean switches that can omit the value) */
-        PROC_CMDLINE_RD_STRICT          = 1 << 2, /* ignore this in the initrd */
-        PROC_CMDLINE_TRUE_WHEN_MISSING  = 1 << 3, /* default to true when the key is missing for bool */
+        PROC_CMDLINE_RD_STRICT          = 1 << 0, /* Only look at options with the "rd." prefix when in the initrd and only
+                                                   * at options without the prefix when not in the initrd.
+                                                   */
+        PROC_CMDLINE_STRIP_RD_PREFIX    = 1 << 1, /* Automatically strip "rd." prefix if we are in the initrd.
+                                                   * When this is specified, the handler function must check for unprefixed
+                                                   * option names. */
+        PROC_CMDLINE_VALUE_OPTIONAL     = 1 << 2, /* The value is optional (for boolean switches that can omit the value). */
+        PROC_CMDLINE_TRUE_WHEN_MISSING  = 1 << 3, /* Make proc_cmdline_get_bool() return true instead of false (the default)
+                                                   * when the key is not present on the command line. */
 } ProcCmdlineFlags;
 
 typedef int (*proc_cmdline_parse_t)(const char *key, const char *value, void *data);