$ git clone -n https://src.fedoraproject.org/rpms/obs-studio.git /var/lib/mock/f40-build-793327-138816/root/chroot_tmpdir/scmroot/obs-studio
Cloning into '/var/lib/mock/f40-build-793327-138816/root/chroot_tmpdir/scmroot/obs-studio'...
$ git fetch origin 721effc0d969bba5736468a377686603173c9ff4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/obs-studio
 * [new ref]         721effc0d969bba5736468a377686603173c9ff4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 721effc Fix i686 build