$ git clone -n https://src.fedoraproject.org/rpms/bustle.git /var/lib/mock/f40-build-2102954-50555/root/chroot_tmpdir/scmroot/bustle
Cloning into '/var/lib/mock/f40-build-2102954-50555/root/chroot_tmpdir/scmroot/bustle'...
$ git fetch origin 26b46d4539fca884dae621269e4cc9f36384b8cd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/bustle
 * [new ref]         26b46d4539fca884dae621269e4cc9f36384b8cd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 26b46d4 bump release