$ git clone -n https://src.fedoraproject.org/rpms/rust-local-channel.git /var/lib/mock/f40-build-2037711-48121/root/chroot_tmpdir/scmroot/rust-local-channel
Cloning into '/var/lib/mock/f40-build-2037711-48121/root/chroot_tmpdir/scmroot/rust-local-channel'...
$ git fetch origin 5f088bbd0648642342459f1b02c7d199164a6568:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-local-channel
 * [new ref]         5f088bbd0648642342459f1b02c7d199164a6568 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5f088bb Update to version 0.1.5; Fixes RHBZ#2246884