$ git clone -n https://src.fedoraproject.org/rpms/rust-random-trait.git /var/lib/mock/f41-build-side-1-3134902-39763/root/chroot_tmpdir/scmroot/rust-random-trait
Cloning into '/var/lib/mock/f41-build-side-1-3134902-39763/root/chroot_tmpdir/scmroot/rust-random-trait'...
$ git fetch origin 337d9cd017896eac2e4582185ee90748e6e4c9ac:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-random-trait
 * [new ref]         337d9cd017896eac2e4582185ee90748e6e4c9ac -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 337d9cd no longer needed