$ git clone -n https://src.fedoraproject.org/rpms/rust-cargo-c.git /var/lib/mock/f40-build-782747-132275/root/chroot_tmpdir/scmroot/rust-cargo-c
Cloning into '/var/lib/mock/f40-build-782747-132275/root/chroot_tmpdir/scmroot/rust-cargo-c'...
$ git fetch origin 987ca275d0f858ab2e08845d009afb383f7eabb3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-cargo-c
 * [new ref]         987ca275d0f858ab2e08845d009afb383f7eabb3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 987ca27 Attempt to work around OOM problems on i686