easyabc.sourceforge.net
EasyABC is an open source abc music notation editor developed by Nils Liberg and released around 2014, now maintained by Jan Wybren de Jong and Seymour Shlien on SourceForge. It displays the musical score and ABC code, plays tunes, and offers syntax highlighting and zoom. It imports MusicXML, MIDI and Noteworthy Composer files and exports to MIDI, SVG and PDF.