$ git clone -n https://github.com/xcp-ng-rpms/libssh2.git /var/lib/mock/v8.3-incoming-10061-28689/root/chroot_tmpdir/scmroot/libssh2
Cloning into '/var/lib/mock/v8.3-incoming-10061-28689/root/chroot_tmpdir/scmroot/libssh2'...
$ git fetch origin afa62337809fbb80282ca47a85cf65e588fd8afc:KOJI_FETCH_HEAD
From https://github.com/xcp-ng-rpms/libssh2
 * [new ref]         afa62337809fbb80282ca47a85cf65e588fd8afc -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at afa6233 Import libssh2-1.11.0-1.xs8.src.rpm