$ git clone -n https://src.fedoraproject.org/rpms/rust-nu-std.git /var/lib/mock/f39-build-1884444-42771/root/chroot_tmpdir/scmroot/rust-nu-std
Cloning into '/var/lib/mock/f39-build-1884444-42771/root/chroot_tmpdir/scmroot/rust-nu-std'...
$ git fetch origin 45071312f7cfcafe5bb0308425746030fab9d385:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-nu-std
 * [new ref]         45071312f7cfcafe5bb0308425746030fab9d385 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4507131 Update to 0.86.0