$ git clone -n https://src.fedoraproject.org/rpms/rust-im-rc.git /var/lib/mock/f41-build-side-1-2992586-36014/root/chroot_tmpdir/scmroot/rust-im-rc
Cloning into '/var/lib/mock/f41-build-side-1-2992586-36014/root/chroot_tmpdir/scmroot/rust-im-rc'...
$ git fetch origin 951aa1ac3785541c53e0e3b4857e9d50bab93ca6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-im-rc
 * [new ref]         951aa1ac3785541c53e0e3b4857e9d50bab93ca6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 951aa1a Remove reference to readme file that is not included in published crates