Screenshot is taken directly from the headset. The game is streamed to the headset wirelessly via Virtual Desktop app with the new foveated streaming feature (you can see the cutoff on the periphery where stuff starts to be more blurry / compressed). In the headset scenes like this (Low lighting with soft shadows) looks extremely atmospheric and really incredible because of the micro oled display and thanks to the new foveated streaming / encoding i finally can safely say compression artefact in wireless PCVR is a thing of the past.
My assumption is, that “fully modded” refers to a state, where the game is like an entire new release (new game or Remaster in example). Partially modded could be in example just changing a few things, without altering the entire game, maybe new weapons or a new character or a region of the map changed. There is no clear definition what these vague terms mean. I just provided a vague answer to a vague question about a vague topic. :D