diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index 7f552a687f..06085ca0ee 100644
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -277,6 +277,10 @@
effective way to fully disable a unit, making it impossible to
start it even manually.
+ Files (including directories) with names that match certain patterns are
+ generally ignored. This includes names that start with a . or
+ end with a .ignore.
+
The unit file format is covered by the
Interface
Portability and Stability Promise.