Building a .mpal file for Musescore 3

I am wanting to create a new palette in Musescore 3, and I am not entirely sure how to create my own palette in .mpal format. I noticed that there isn't notation centered text, and I would like to contribute towards that empty zone on the program.

I also know that there are updated versions of Musescore out there, but I still prefer to use 3 for other reasons. Any help would be amazing!

Thank you!