$ git clone -n https://src.fedoraproject.org/rpms/copr-backend.git /var/lib/mock/f39-build-1600437-38537/root/chroot_tmpdir/scmroot/copr-backend
Cloning into '/var/lib/mock/f39-build-1600437-38537/root/chroot_tmpdir/scmroot/copr-backend'...
$ git fetch origin 609288e01974590cc3b06ae17ededbe98fedec9b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/copr-backend
 * [new ref]         609288e01974590cc3b06ae17ededbe98fedec9b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 609288e Update copr-backend to 1.172-1