Wikipedia
TuxGuitar
TuxGuitar is a free, open source tablature editor, which includes features such as tablature editing, score editing, and import and export of Guitar Pro gp3, gp4, and gp5 files. In addition, TuxGuitar's tablature and staff interfaces function as basic MIDI editors.
TuxGuitar's mascot and namesake is Tux, the penguin mascot of many games and programs originally designed for Linux.
The program is written in the Java programming language and is released under version 2.1 of the GNU Lesser General Public License.
TuxGuitar 1.2 was released in 2009. Its source code was steadily updated through 2015 culminating in a release of version 1.3.0 in January 2016.