$ git clone -n https://src.fedoraproject.org/rpms/rust-fd-lock.git /var/lib/mock/f40-build-2270916-54867/root/chroot_tmpdir/scmroot/rust-fd-lock
Cloning into '/var/lib/mock/f40-build-2270916-54867/root/chroot_tmpdir/scmroot/rust-fd-lock'...
$ git fetch origin 66c6cb90a295e14bc53bddb51be4695a1b06cc10:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-fd-lock
 * [new ref]         66c6cb90a295e14bc53bddb51be4695a1b06cc10 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 66c6cb9 Update to version 4.0.2; Fixes RHBZ#2218701