$ git clone -n https://src.fedoraproject.org/rpms/golang-github-libgit2-git2go.git /var/lib/mock/f38-build-side-42-init-devel-652704-26521/root/chroot_tmpdir/scmroot/golang-github-libgit2-git2go
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-652704-26521/root/chroot_tmpdir/scmroot/golang-github-libgit2-git2go'...
$ git fetch origin e309383bb58c24ef9794b33cf87cd993895375e8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/golang-github-libgit2-git2go
 * [new ref]         e309383bb58c24ef9794b33cf87cd993895375e8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e309383 Update to latest version (#2132454)