$ git clone -n https://src.fedoraproject.org/rpms/mozjs102.git /var/lib/mock/f41-build-847222-163846/root/chroot_tmpdir/scmroot/mozjs102
Cloning into '/var/lib/mock/f41-build-847222-163846/root/chroot_tmpdir/scmroot/mozjs102'...
$ git fetch origin 875827a48e5749d1f43d2bd85de6f393c2f0a1ae:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mozjs102
 * [new ref]         875827a48e5749d1f43d2bd85de6f393c2f0a1ae -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 875827a Add support for riscv64