diff --git a/help.c b/help.c
index 1dfa0b0582..02ba043319 100644
--- a/help.c
+++ b/help.c
@@ -397,6 +397,10 @@ const char *help_unknown_cmd(const char *cmd)
 
 int cmd_version(int argc, const char **argv, const char *prefix)
 {
+	/*
+	 * The format of this string should be kept stable for compatibility
+	 * with external projects that rely on the output of "git version".
+	 */
 	printf("git version %s\n", git_version_string);
 	return 0;
 }