$ git clone -n https://src.fedoraproject.org/rpms/rust-nu.git /var/lib/mock/f40-build-807460-145221/root/chroot_tmpdir/scmroot/rust-nu
Cloning into '/var/lib/mock/f40-build-807460-145221/root/chroot_tmpdir/scmroot/rust-nu'...
$ git fetch origin 9c2b99c4c4e3dc9281950cc5328b234625fa0583:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-nu
 * [new ref]         9c2b99c4c4e3dc9281950cc5328b234625fa0583 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9c2b99c Update to 0.91.0 (rhbz#2267997)