Okay, after some playing around and experimentation, here's what I have discovered: Without SASL, NONE of the Aspen works. Neither the graphics, nor the logic, nor the pop-up window, nor its interaction with the autopilot, nor the knobs, nor the click zones, etc. It appears the way it's programmed, it makes use of some pixel graphics, some fonts, and some vector graphics. Functionality seems to be all programmed from scratch, tapping into some X-Plane datarefs, but most of the datarefs are custom. There's NOTHING "X-Plane default" about this Aspen. Not the graphics (ALL graphics are high-quality, high-resolution custom graphics), not the logic, not the pop-up functionality. Only some datarefs used to display stuff like artificial horizon are X-Plane's and even these datarefs are subject to custom plugin commands to reflect the real EFD1000's functionality. Even the database used to show the moving map is custom-compiled and calling in this database is done with SASL. Drawing the stuff on the map is done with SASL as well. X-Plane's datarefs are used also to interact with the Aspen, so that things like Moving Map de-cluttering and zoom functionality or barometer settings or speed, altitude, and heading bugs are in sync with X-Plane's commands. The source files are not locked. It's all there: the graphics, the code, even SASL as a plugin is open-source, so you can feel free to look under the hood all you want. I'm attaching some screenies of the EFD1000 popup showing the menu pages.EFD1000_screenies.zip