Development Discussion Board

If you're asking how to improve your indexing on search engines then you should post on our main site: https://www.phpbb.com/community/index.php

Area 51 is for phpBB development-related discussion.

If we did that then what would be the next step?

Not even sure we understand the question since searching through all posts in a forum is exactly what the search form indicates it does.

How is it harder to write an extension for this than before? Certainly a lot of work, but not more work now than it would have been when extensions came out some 5+ years ago

It is.

3.1 line is no longer supported.

Support is at: https://www.phpbb.com/community

Nope. You need to do that through an FTP client.

Pretty much all of those things should be done by extensions. What you "need" many others don't need or even want.

Report it in the Customisations DB tracker as the demo doesn't have anything to do with phpBB itself.