$ git clone -n https://src.fedoraproject.org/rpms/ghc-either.git /var/lib/mock/f38-build-side-42-init-devel-1044825-29761/root/chroot_tmpdir/scmroot/ghc-either
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1044825-29761/root/chroot_tmpdir/scmroot/ghc-either'...
$ git fetch origin e93cfd42c7c04782a3ebefb3d33e46b3970c17d5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-either
 * [new ref]         e93cfd42c7c04782a3ebefb3d33e46b3970c17d5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e93cfd4 Convert to %autorelease and %autochangelog