Standard from 2011: abcnotation.com/wiki/abc:standard:v2.1
No bend/vibratto/slides :-(
Multitrack volatile: abcnotation.com/wiki/abc:standard:v2.1#multiple_voices
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ABC notation is a simple and compact way to represent music using plain text. It is particularly popular for notating folk music and traditional tunes, as it allows musicians to easily share and exchange musical scores through text files or online. The notation uses letters from the English alphabet to denote pitches (A through G), with various symbols and characters to indicate rhythm, duration, and other musical elements.