Basically when you add a content warning on Masto it’ll just display that content warning in people’s feeds but hide the actual content, unless they choose to click and expand. Blurs any attached images too. So you sort of know what you’re in for if something is marked “CW: pet loss” for example, and can choose whether that’s something you want to look at.

I think there’s a setting somewhere to automatically expand CW posts if you’re not fussed about things like that, but it’s helpful for people who do have a common trigger.

Pretty slick feature tbh!