diff --git a/doc/comitium.1.scd b/doc/comitium.1.scd
index 5d5b023..b4b6308 100644
--- a/doc/comitium.1.scd
+++ b/doc/comitium.1.scd
@@ -133,6 +133,13 @@ Within the data directory, the following files are used:
 	contents of *feed.gmi* will be appended to the contents of *header.gmi*
 	separated by one newline.
 
+*footer.gmi*
+	This file is neither created nor modified by comitium.  If it exists and is
+	nonempty, then it is read and used as a custom footer for *feed.gmi* and
+	*subscriptions.gmi*.  If it doesn't exist or is empty, then a default footer
+	is used.  Note the link "aggregated using comitium vX.X.X" will always be
+	appended to ensure that all instances are compliant with the AGPL.
+
 *feed.gmi*
 	The outputted text/gemini file containing the subscription items. Is what
 	should be linked or copied to your server directory to publish it.