MuSIC-TeN is a loose acronym standing for "Musical Score Interpretation Compact-Text Notation". The notation system is open source, in the sense that it can be used and modified without restrictions. It is authored by the same team that created the MuSIC-TeN Pianos app. At present the spec is available in PDF format downloadable below and the document is also distributed with MuSIC-TeN Pianos internally and can be loaded from within the app.
The notation system has a formal syntax (or grammar if you will) that can be described through a set of Backus-Naur production rules. That makes it amenable to being parsed by software programs. The philosophy behind it is that piano sheet music gets manually translated into this notation and in the process, the human translator impresses his or her own personal interpretation of the sheet music in terms of tempo variations, rubato, dynamic level variations, in unequivocal and unambiguous terms, captured by the notation syntax. This process is referred to as "score personalization". For that the translator must be able to read sheet music to some degree but not to play piano.
MuSIC-TeN Pianos can assist with score personalization through its interactive timing feature, which allows the user to inject tempo variations into a MuSIC-TeN score in an interactive way, by using the computer keyboard/mouse.
MuSIC-TeN Pianos embeds a small editing box in which MuSIC-TeN content can be added and played immediately. Notes can be entered manually or captured from keys pressed on the piano with the mouse or computer keyboard.