Given my limited knowledge about its source code - it seems to use only the permissions required and executes a minimal amount of code.

The color tones are 5/5, no inverted colors or bug. The only problem is that when you reload or when you load in instagram the screen is bright white and my eyes die.

As of this writing, the add-on seems to be working perfectly.

This is just a great app! Everything is clearly visible without additional settings!