In 1992 Martin Leclerc and Mario Dorion developed a simple text file format to write lead sheets, songs with lyrics and chords, and a tool to create neatly printed lead sheets out of these text files. The tool was called chord, and the text files were called chord files. It soon became a popular way to write lead sheets and many users and tools adopted this format for similar purposes. For still unknown reasons people started calling the files chordpro files.

www.chordpro.org/chordpro

The ChordPro (also known as Chord) is an ASCII text file format for transcribing songs with chords and lyrics. The format was originally used for guitar, but is used for variety of other string instruments, such as ukulele, bass guitar or mandolin. Although this format is legible as it is, there are many popular programs for displaying, transposing and printing. Files in this format often have extensions such as .crd, .chopro, .pro, .chordpro or .cho.

en.wikipedia.org/wiki/ChordPro

Downloads ~ github.com/ChordPro/chordpro/releases

Related:

Chord_ii ~ www.vromans.org/johan/projects/Chordii/intro