WordPress allows themes to support wide and full alignment, which could be useful for things like full width page headers. In fact it's probably hard to implement those without this.

If we add set a theme support flag, some blocks such as images will display wide alignment options. This now only depends on the editor width config in theme.json.

For now we opt out of the wide alignment option, and only add the full width option.

As a result of this ticket, every core block that supports wide alignment will have this option available.

Heads up: We haven't tested this extensively on every core block yet (there's a lot of them). So if you use this option please check if it has the desired result for your content before publishing. It's also possible that child theme CSS prevents it from working properly.

https://www.billerickson.net/full-and-wide-alignment-in-gutenberg/ 

https://make.wordpress.org/core/2021/06/29/on-layout-and-content-width-in-wordpress-5-8/