I've seen markdown projects leverage link syntax for custom extensions, e.g. [click me](button://).
Markdown also supports embedded HTML. Perhaps you could add custom tags for extensions?
miniblog.
Related Posts
Wikipedia is overhauling its theme! https://diff.wikimedia.org/2020/09/23/wikipedia-is-getting-a-new-look-for-the-first-time-in-10-years-heres-why/
I have sometimes installed CSS tinkering extensions just to fix the line length on desktop, so I'm glad to hear that's getting fixed.
A critique of RISC design, and why CPUs end up with custom instructions: https://blackhole12.com/blog/risc-is-fundamentally-unscalable/
(RISC-V has explicit support for extensions, so I think it will be less of an issue there. The idea that webassembly will make programs more portable is interesting.)
Exploring JVM extensions to add proper reified generics to Java! You'll be able to distinguish List<Integer> from List<String> (i.e. not just type erasure).
https://openjdk.java.net/jeps/8204937
