$ git clone -n https://src.fedoraproject.org/rpms/libheif.git /var/lib/mock/f38-build-side-42-init-devel-680384-26737/root/chroot_tmpdir/scmroot/libheif
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-680384-26737/root/chroot_tmpdir/scmroot/libheif'...
$ git fetch origin ebbbb8cd0971cc2a854feb99a60547f48505eac0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libheif
 * [new ref]         ebbbb8cd0971cc2a854feb99a60547f48505eac0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ebbbb8c Fix conditional for RHEL again