VersionPress\Storages\MetaEntityStorage::createJoinedKey PHP Method

    protected function createJoinedKey($key, $vpId)
    {
        return sprintf('%s#%s', $key, $vpId);
    }

 protected function createJoinedKey($key, $vpId)
 {
     $key = $this->maybeReplacePrefixWithPlaceholder($key);
     return parent::createJoinedKey($key, $vpId);
 }