diff --git a/doc/snac.5 b/doc/snac.5
index 1b28d25..0168430 100644
--- a/doc/snac.5
+++ b/doc/snac.5
@@ -209,6 +209,8 @@ web interface.
 .It Pa history/
 This directory contains generated HTML files. They may be snapshots of the
 local timeline in previous months or other cached data.
+.It Pa server.pid
+This file stores the server PID in a single text line.
 .El
 .Sh SEE ALSO
 .Xr snac 1 ,