This is yet another GPS clock. However, this one also includes a PROGMEM based menuing system library. In this system, menus are defined by JSON structures, with function pointers for callbacks when the menu items are selected (typically by rotary encoder or other arrow-button-based UI).
You can get a copy of the repo at this URL (copy the URL, then 'git clone' it). Sorry for the weird URL, but it will work for any complete static mirror of this web page.
There is also some work in assembling a complete list of custom MediaTek/MTK GPS commands. A lot of current GPS devices are based off the same MediaTek chipset, which contains a bunch of custom commands. Not all of these are enabled in all firmwares, but the documentation for each firmware typically leaves out some of the commands that are enabled, so having a complete list is handy. This is in the mtk_doc/ subdirectory of the git repo.
I'll put up a better explanation of all this soon enough.-jbm