So when browsing Steam games, I've noticed two distinct "Mature Content" warnings:
However, recently I've started seeing a different warning, which says "Content in this product may not be appropriate for all ages, or may not be appropriate for viewing at work", and then simply asks you to continue or cancel. It looks like this: (the "continue" and "cancel" buttons were cropped out accidentally)
What does Steam use to determine which to show?
(Related side questions: Are there other possible warnings? Why do some M-rated games not get either of the warnings, like The Witcher 3?)