$ git clone -n https://src.fedoraproject.org/rpms/rust-jxl-color.git /var/lib/mock/f40-build-2037443-48097/root/chroot_tmpdir/scmroot/rust-jxl-color
Cloning into '/var/lib/mock/f40-build-2037443-48097/root/chroot_tmpdir/scmroot/rust-jxl-color'...
$ git fetch origin 5960002378b24e8f67c76e6965ad712498a7df78:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-jxl-color
 * [new ref]         5960002378b24e8f67c76e6965ad712498a7df78 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5960002 Initial Fedora packaging (rhbz#2248920)