diff --git a/man7/cgroups.7 b/man7/cgroups.7
index 19a6be9dc..c4e1f2102 100644
--- a/man7/cgroups.7
+++ b/man7/cgroups.7
@@ -493,6 +493,14 @@ the value in this file is inherited from the corresponding file
 in the parent cgroup.
 .\"
 .SH CGROUPS VERSION 2
+.\" FIXME
+.\" Document the 'nsdelegate' mount option added in Linux 4.13
+.\" To test this, it can be useful to boot the kernel with the options:
+.\"
+.\"    cgroup_no_v1=all systemd.legacy_systemd_cgroup_controller
+.\"
+.\" The effect of th latter option is to prevent systemd from employing
+.\" its "hybrid" cgroup mode, where it tries to make use of cgroups v2.
 In cgroups v2,
 all mounted controllers reside in a single unified hierarchy.
 While (different) controllers may be simultaneously