[ForceBru]

I thought it should be extremely portable ("everything just works, it's native"), but it doesn't work on iOS 9.3.6. It doesn't even let me input text into the textarea...

A natural extension seems to be a source code editor with syntax highlighting, like those used in https://marimo.io/, Jupyter, https://plutojl.org/ and other notebook-like Web editors.

[acherion]

I'm not sure why you are testing in iOS 9.3.6. (which was released in 2015), when the documentation says support for Safari is for versions 16 and above.

[ForceBru]

Well, as I said, I thought this should work everywhere because it's just a textarea, so I didn't read the docs and rushed to test my hypothesis on an old and widely unsupported device