Frescobaldi is an IDE for editing musical scores, or rather input files to be used with the GNU LilyPond notation software. While it tries to provide the most convenient and "graphical" user interface for working with scores it essentially sticks to its core responsibility of being a text editor.

Frescobaldi is written in Python 3 and PyQt5, which makes it very accessible for new contributors, the clean project architecture providing a comparably shallow learning curve. By engaging with Frescobaldi as a GSoC student you will also engage with the (user and developer) Community of GNU LilyPond, which is a very active and knowledgeable community.