$ git clone -n https://src.fedoraproject.org/rpms/xdelta.git /var/lib/mock/f45-build-38670-727/root/chroot_tmpdir/scmroot/xdelta
Cloning into '/var/lib/mock/f45-build-38670-727/root/chroot_tmpdir/scmroot/xdelta'...
$ git fetch origin 6d980b4680c124a075b32f020d2c468a7231bcc8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xdelta
 * [new ref]         6d980b4680c124a075b32f020d2c468a7231bcc8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6d980b4 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild