$ git clone -n https://src.fedoraproject.org/rpms/erlang-merge_index.git /var/lib/mock/f39-build-1541746-36507/root/chroot_tmpdir/scmroot/erlang-merge_index
Cloning into '/var/lib/mock/f39-build-1541746-36507/root/chroot_tmpdir/scmroot/erlang-merge_index'...
$ git fetch origin b361d8ee31357b43ec22fdf8979a355c6a8e2592:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/erlang-merge_index
 * [new ref]         b361d8ee31357b43ec22fdf8979a355c6a8e2592 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b361d8e Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild