$ git clone -n https://src.fedoraproject.org/rpms/libb2.git /var/lib/mock/f40-build-2219675-52640/root/chroot_tmpdir/scmroot/libb2
Cloning into '/var/lib/mock/f40-build-2219675-52640/root/chroot_tmpdir/scmroot/libb2'...
$ git fetch origin dd0a832babb48c6f2add43c9226a35bfc8c88b28:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libb2
 * [new ref]         dd0a832babb48c6f2add43c9226a35bfc8c88b28 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at dd0a832 Migrate to SPDX license