How the module is put together and the interfaces it exposes to your code. Pick the row for the question you have.
| I want to ... | Use | Needs |
|---|---|---|
| see how the field, the editor and the front-end script work together | Architecture | Nothing |
| know what each submodule provides | Submodules | Nothing |
| learn the class naming scheme and how it meets Bootstrap | CSS architecture | CSS |
| add utility classes, icon sets or alter the field render array | Hooks API reference | A custom module |
| call PHP services, JavaScript extension points or HTTP routes | API reference | A custom module |
| call the AI routes the editor uses for text, images and pages | AI API reference | AI set up on the site |
Which should I use
Start with the architecture page; the others assume its picture of the field, the editor and the front-end script. Use the hooks for small changes from a module, and the API reference when you integrate another system.