$ git clone -n https://src.fedoraproject.org/rpms/rust-relative-luminance.git /var/lib/mock/f45-build-44415-813/root/chroot_tmpdir/scmroot/rust-relative-luminance
Cloning into '/var/lib/mock/f45-build-44415-813/root/chroot_tmpdir/scmroot/rust-relative-luminance'...
$ git fetch origin e39a9f13a5ef96bb6e1262d65c7c956efafb599b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-relative-luminance
 * [new ref]         e39a9f13a5ef96bb6e1262d65c7c956efafb599b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e39a9f1 Simplify .gitignore