$ git clone -n https://src.fedoraproject.org/rpms/jpegxl.git /var/lib/mock/f41-build-850524-165462/root/chroot_tmpdir/scmroot/jpegxl
Cloning into '/var/lib/mock/f41-build-850524-165462/root/chroot_tmpdir/scmroot/jpegxl'...
$ git fetch origin e87d18bbd6054e7190ce9a6db25aa8dbd3c99563:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jpegxl
 * [new ref]         e87d18bbd6054e7190ce9a6db25aa8dbd3c99563 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e87d18b Disable gimp_plugin, jpegxl don't support Gimp 3 yet