Behaviors: Move behaviors code to experimental folder.

[cbravobernal]

What?

Behaviors are not getting to 6.3. Due to that reason, the code should still be in experimental.

[github-actions]

Flaky tests detected in a17dfb1.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/5312382341
📝 Reported issues:

• [Flaky Test] ensures paragraph block toolbar uses roving tabindex #49733 in /test/e2e/specs/editor/various/toolbar-roving-tabindex.spec.js

[artemiomorales]

I don't know enough about how the experimental/ versus compat/ folders work and their implications to offer an approving review, though I can say that I've tested the lightbox functionality and all seems to working as expected 👍

[ramonjd]

This makes sense to me.

PHP changes in /compat/x-y folders correspond to features that have been synched to the x.y releases of WordPress.

It means, for example, that folks who are still running, say, WordPress 6.2, can still use 6.3-compatible features if they have the Gutenberg plugin installed. It also acts as a guide for us so that we have a good idea about which features have made it to Core and which haven't 😄

More info over at the README:

gutenberg/lib/README.md

Line 1 in 32d394c

# Gutenberg PHP

So if the changes in this PR are not being ported to WordPress 6.3 then I think /experimental is a valid place for them to live until they're stable/earmarked for a WordPress release.

Thanks!

[SantosGuillamot]

Looks good to me 🙂