Some PRETTY FORMATS format:<string> options don't work with git-archive export-subst $Format:$

I first noticed this using the system git provided in Fedora 21, so I
cloned the official git repo, built from source, and it would appear
there are even more options that don't work with export-subst in the
latest code.

I tested this under commit 63a45136a329bab550425c3142db6071434d935e
(HEAD, origin/master, origin/HEAD, master).

Take, for example, the following script:

FILE=Foo.pm
DIR=$(mktemp -d /tmp/git.XXXXXX)
cd $DIR
git init
echo '*.pm export-subst ident' >> .gitattributes
echo '#   Last Author    : $Author: $Format:%an$ $' > $FILE
echo '#   Last Date      : $Date: $Format:%ai (%ad)% $' >> $FILE
echo '#   Last Version   : $Revision: $Format:%d$ $' >> $FILE
echo '#   Last Version v2: $Revision: $Format:%D$ $' >> $FILE
echo '#   Last Commit    : $Commit: $Format:%H$ $' >> $FILE
echo '#   This File      : $Id$' >> $FILE
echo 'our $VERSION = (qw($Format:%N$))[1];' >> $FILE
git add .
git commit -a -m "Initial commit."
git notes add -f -m '$Release: 0048 $'
git tag -f releases/R0048
git archive HEAD $FILE | tar xf - --to-stdout
rm $FILE
git checkout -- $FILE
cat $FILE
git log --format='%N' -1


You can tell I'm attempting to recreate CVS keywords (bwahahaa!) for a
project that is insisting they need them.

I'd be happy to write a bunch of unit tests for export-subst and all
PRETTY FORMATS format:<string> options, if that would be desirable. I
see the t/ directory, and the t/test-lib.sh stuff looks simple enough
(TAP in bash, hmm).

Thanks,

Derek