Oxygen
This is the first release of html-stream-non-namespaced.
This repository is completely codegenned, since we publish html-stream-namespaced alongside it. We have not changed the codegen at all before building the open source version of html-stream. I hope I can open source the codegen code itself within the coming weeks. It is nothing special, but it would allow you to change the html tags and add new ones.
If you have non-xhp code that is using invalid attributes on html tags, xhp does not accept them. If this is blocking you from migrating that codepath to xhp, you could add those attributes (temporarily) to the affected tags by editing the definition json files.
If you wanted to add methods to all sgml-stream elements in your system, you could write them in a trait. You could use that trait in your own UserElements, but you would need access to the codegen to inject them into the html tags. You can introduce xhp-lib methods you use in your code into your own version of sgml-stream this way. (You can't add mutating methods, since sgml-stream elements are immutable. See sgml-stream's docs for more information.)