$ git clone -n https://src.fedoraproject.org/rpms/plasma-vault.git /var/lib/mock/f42-build-side-1-3505197-45989/root/chroot_tmpdir/scmroot/plasma-vault
Cloning into '/var/lib/mock/f42-build-side-1-3505197-45989/root/chroot_tmpdir/scmroot/plasma-vault'...
$ git fetch origin 1751f88802e3a9cf80b4168bdef0acbdf7fd9d11:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-vault
 * [new ref]         1751f88802e3a9cf80b4168bdef0acbdf7fd9d11 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1751f88 6.3.4