$ git clone -n https://src.fedoraproject.org/rpms/jpegxl.git /var/lib/mock/f40-build-789148-135664/root/chroot_tmpdir/scmroot/jpegxl
Cloning into '/var/lib/mock/f40-build-789148-135664/root/chroot_tmpdir/scmroot/jpegxl'...
$ git fetch origin abc05881f43a5980daaf6e5524ad6253fcf6ad9e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jpegxl
 * [new ref]         abc05881f43a5980daaf6e5524ad6253fcf6ad9e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at abc0588 Drop unused build dependencies