$ git clone -n https://src.fedoraproject.org/rpms/libdkimpp.git /var/lib/mock/f45-build-16064-481/root/chroot_tmpdir/scmroot/libdkimpp
Cloning into '/var/lib/mock/f45-build-16064-481/root/chroot_tmpdir/scmroot/libdkimpp'...
$ git fetch origin 7cebb6e1d4d3cfe7b59e1de04cb7bfb0907b0a47:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libdkimpp
 * [new ref]         7cebb6e1d4d3cfe7b59e1de04cb7bfb0907b0a47 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7cebb6e libdkimpp: 2.4.1 release