$ git clone -n https://src.fedoraproject.org/rpms/rust-gix-index.git /var/lib/mock/f41-build-side-1-3006374-36745/root/chroot_tmpdir/scmroot/rust-gix-index
Cloning into '/var/lib/mock/f41-build-side-1-3006374-36745/root/chroot_tmpdir/scmroot/rust-gix-index'...
$ git fetch origin c4df37fb45d0f2cdbc90cf1378b4357c6aecf9f6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gix-index
 * [new ref]         c4df37fb45d0f2cdbc90cf1378b4357c6aecf9f6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c4df37f Update to version 0.35.0 (rhbz#2307385)