Removing the post format (type) slug
In your last code example, you’re returning a wrong type for the post_format_rewrite_base. It should be a string, not an array. However, your idea goes in the right direction. You have to take care about all the «routes» that are implied by the default rewrite rules, WordPress creates for post formats: type/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$ => index.php?post_format=$matches[1]&feed=$matches[2] type/([^/]+)/(feed|rdf|rss|rss2|atom)/?$ … Read more