Apparently, an important part that was missing in my description is that this is a two-step process: (1) The community (or even you alone, or some (commercial)

Apparently, an important part that was missing in my description is that this is a two-step process: (1) The community (or even you alone, or some (commercial) provider) tags the source material with categories and severities of things that can be filtered. (2) Either in the UI of the video player (if supported), or using the currently provided "transpiler", you get to choose what you want to filter and what you want to see. Sorry for having forgotten to explain this in a prominent place!