repo-add.8.txt: document valid DB file extensions

Signed-off-by: Dave Reisner <d@falconindy.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/doc/repo-add.8.txt b/doc/repo-add.8.txt
index 01968827..2de5be8f 100644
--- a/doc/repo-add.8.txt
+++ b/doc/repo-add.8.txt
@@ -29,6 +29,11 @@ command line.
 delta specified on the command line. Multiple packages and/or delta to remove
 can be specified on the command line.
 
+A package database is a tar file, optionally compressed. Valid extensions are
+``.db'' or ``.files'' followed by an archive extension of ``.tar'',
+``.tar.gz'', ``.tar.bz2'', or ``.tar.xz''. The file does not need to exist, but
+all parent directories must exist.
+
 
 Common Options
 --------------