From the author:
MapTrek is an open source softwareMapTrek is developed as a hobby for personal use but is generously shared to public on as-is basis. Developers are welcome to contribute to the project. Specifically experts in OpenGL and PostGIS are much needed.The development is managed on GitHub, there you can find the source code and the list of open issues
If you don't use any propietary lib or Play Services or things like that it could be added...
Requests for application inclusion should be made on GitLab, so better open a report there: