$ git clone -n https://src.fedoraproject.org/rpms/jpegxl.git /var/lib/mock/f38-build-721708-98611/root/chroot_tmpdir/scmroot/jpegxl
Cloning into '/var/lib/mock/f38-build-721708-98611/root/chroot_tmpdir/scmroot/jpegxl'...
$ git fetch origin 3b31ff8895fe7b15a7af6c89162fc96feaa71d48:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jpegxl
 * [new ref]         3b31ff8895fe7b15a7af6c89162fc96feaa71d48 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3b31ff8 Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild