$ git clone -n https://github.com/xcp-ng-rpms/swtpm.git /var/lib/mock/v8.3-incoming-9861-28583/root/chroot_tmpdir/scmroot/swtpm
Cloning into '/var/lib/mock/v8.3-incoming-9861-28583/root/chroot_tmpdir/scmroot/swtpm'...
$ git fetch origin badc276525e92312f1d9b8f750a823b3e14ccc51:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/swtpm
 * [new ref]         badc276525e92312f1d9b8f750a823b3e14ccc51 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at badc276 Merge pull request #2 from xcp-ng-rpms/8.3-rebase-XS-0.7.3-12