graph: add commit graph design document

diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt
index 4edd09fc6b0742042f3236598d8ecb793773d8ab..14da5fc157ee0ea7467e7b9bd9d33d465c1f7a3f 100644 (file)
--- a/Documentation/git-config.txt
+++ b/Documentation/git-config.txt
@@ -180,6 +180,11 @@ See also <<FILES>>.
        value (but you can use `git config section.variable ~/`
        from the command line to let your shell do the expansion).
 
+--expiry-date::
+       `git config` will ensure that the output is converted from
+       a fixed or relative date-string to a timestamp. This option
+       has no effect when setting the value.
+
 -z::
 --null::
        For all options that output values and/or keys, always