Twenty Twenty Two Compatibility

[jeherve]

Twenty Twenty Two is expected to ship with WordPress 5.9 at the end of the year. It is currently being developed here:
https://github.com/WordPress/twentytwentytwo

In the past, and with previous default themes, we've added a number of compatibility files and functions to make sure new WordPress site owners had the best experience they could get when using the default theme and Jetpack. In practice, it meant adding the following:

• Add Infinite Scroll support and tweak CSS to make sure the IS buttons look good.
• Tweak CSS for Sharing buttons / Likes / Related Posts
• Alter Gallery widget default width.
• Style all Jetpack widgets to match the style of the theme.
• Add Content Options support
• Ensure that sharing buttons and Likes are not hooked into the excerpt when one is added to a post.

**It's worth noting that Twenty Twenty Two will be a FSE theme, so we may not want to implement all those things this time around.

Previous art on this

• Twenty Twenty One Twenty Twenty One Compatibility #17248

[jeherve]

Tweak CSS for Sharing buttons / Likes / Related Posts

• Related Posts can be added to any template via a block.
• Sharing buttons and Likes appear to be displayed properly, I don't think any adjustment is necessary.

[jeherve]

Alter Gallery widget default width.
Style all Jetpack widgets to match the style of the theme.

Since it's an FSE theme, I do not think we need to worry too much about widgets, since there is no widget area.

[jeherve]

Add Content Options support

Since it's an FSE theme, there is no customizer and content can be customized in templates. We do not need to worry about this here.

[jeherve]

Add Infinite Scroll support

I do not think this will be an option here, since block themes do not use PHP templates that I could call to render a single post or a loop of posts from Infinite Scroll.

Infinite Scroll will need to be adapted to work with FSE themes. Tracking this in #21787.