$ git clone -n https://src.fedoraproject.org/rpms/rust-local-channel.git /var/lib/mock/f39-build-1526460-36068/root/chroot_tmpdir/scmroot/rust-local-channel
Cloning into '/var/lib/mock/f39-build-1526460-36068/root/chroot_tmpdir/scmroot/rust-local-channel'...
$ git fetch origin d6b4571281fa3bfde61011592f12c10ea75457fc:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-local-channel
 * [new ref]         d6b4571281fa3bfde61011592f12c10ea75457fc -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d6b4571 Update to version 0.1.4; Fixes RHBZ#2239346