Developers
The architecture of an installed XPAC plugin, plus generated reference for every block and hook XPAC ships.
An XPAC plugin is a WordPress plugin assembled from PHP packages. Its entry file
loads the Composer autoloader and constructs one Bootstrap per package; the
packages live under packages/; the compiled JavaScript, CSS and block metadata
live under dist/; the framework they all run on lives under vendor/.
Every plugin in the suite has that shape. That is why the reference below applies
across all of them, and why a path like
packages/Forms/core/base/Uploader.php:349 on a hook page is a path you can open
on your own server.
This section has two halves, and they are maintained in completely different ways.
Hand-written guides
Architecture and conventions. Written by hand, which means they can go stale — every claim on these pages cites the file it came from so you can check.
Generated reference
These pages are generated from the source, so they cannot describe a block that is not registered or a hook that is not fired — they are built from the same files WordPress reads.
Blocks
Every registered block, generated from the block.json files each plugin ships under dist/.
Hooks
Every action and filter, generated from the do_action and apply_filters call sites under packages/.
Where a guide and the generated reference disagree, the generated reference is right. Report the guide.