Anything that is part of the official HTML spec is likely welcome.
Common patterns of web development, or ease-of-use features are welcome, so long as they are general and are likely to be useful to a broad group and not targetting any specific implimentation.
All PRs must have 100% test coverage of new code.
New features should include example usage, including motivations.
For exceptions to these, see #Community
Do not add 3rd party dependencies.
I am not interested in maintaining integrations with a bunch of random JS/web frameworks/libraries. (i.e. HTMX, Flask, Unpoly, whatever)
If you wish to add a feature that would otherwise be disallowed by the above, you can make a community package. See community/htmx.py for a trivial example.
Community packages must not be referenced from the main library, and must not do anything unless explicitly imported.