$ git clone -n https://src.fedoraproject.org/rpms/libheif.git /var/lib/mock/f41-build-811531-147423/root/chroot_tmpdir/scmroot/libheif
Cloning into '/var/lib/mock/f41-build-811531-147423/root/chroot_tmpdir/scmroot/libheif'...
$ git fetch origin b773ffe517c0be97aed5732eae000839eb6561c2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libheif
 * [new ref]         b773ffe517c0be97aed5732eae000839eb6561c2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b773ffe Update to 1.17.6