I've found vextab [1] though it doesn't seem to be maintained anymore, and of course there are plenty of ASCII-art formats (GuitarPro et al) though these are really renderers, not markup (in other words, I want to _generate_ renders, not have to type them).

LilyPond [2] is neat, but of course much too verbose to jot down in semi-realtime.

I've started writing a language spec [3] and renderer [4], but surely someone else has had this idea before??

```catl # chords: X554X5 ```

```catl # tabs: # ↓chord 0A 0D 5e 7B 3e+0D ```

---

[1] https://vexflow.com/vextab/tutorial.html [2] https://lilypond.org/ly-examples/tab-example.ly [3] https://github.com/j6k4m8/catl [4] https://github.com/j6k4m8/catl-render