$ git clone -n https://src.fedoraproject.org/rpms/webkit2gtk4.0.git /var/lib/mock/f42-build-3348167-45005/root/chroot_tmpdir/scmroot/webkit2gtk4.0
Cloning into '/var/lib/mock/f42-build-3348167-45005/root/chroot_tmpdir/scmroot/webkit2gtk4.0'...
$ git fetch origin 9899f01cd237bd2b80933551c2db46829a7950d3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/webkit2gtk4.0
 * [new ref]         9899f01cd237bd2b80933551c2db46829a7950d3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9899f01 Rebuild for jpegxl (libjxl) 0.11.1