$ git clone -n https://src.fedoraproject.org/rpms/wlroots0.19.git /var/lib/mock/f45-build-38438-724/root/chroot_tmpdir/scmroot/wlroots0.19
Cloning into '/var/lib/mock/f45-build-38438-724/root/chroot_tmpdir/scmroot/wlroots0.19'...
$ git fetch origin b29d9cc859e80e6f0c1415ddcab26afeccb20f79:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/wlroots0.19
 * [new ref]         b29d9cc859e80e6f0c1415ddcab26afeccb20f79 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b29d9cc Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild