$ git clone -n https://src.fedoraproject.org/rpms/jakarta-mail.git /var/lib/mock/f40-build-2075715-49510/root/chroot_tmpdir/scmroot/jakarta-mail
Cloning into '/var/lib/mock/f40-build-2075715-49510/root/chroot_tmpdir/scmroot/jakarta-mail'...
$ git fetch origin 1bbceb0a2ea80d77c27cffd7471401dfcf4b88ad:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jakarta-mail
 * [new ref]         1bbceb0a2ea80d77c27cffd7471401dfcf4b88ad -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1bbceb0 Update javapackages test plan to f40