The implementation is similar to the one found on Instagram. Which is in turn is a lot like Google’s Digital Wellbeing, found on YouTube and Android 9 Pie. You can check the amount of time you spend on the app and even set soft limits on it. The limit then chimes in as a reminder that you’ve used it for longer than you wanted.

We already have this option on our Facebook app at the time of writing, and from the looks of it, the recorded time spent is strictly based on the device you’re using. It’s not on the web version of Facebook, and using it on a browser doesn’t seem to count towards the feature’s quota. (Source: TechCrunch) Edited by John Law

Facebook Rolls Out Dashboard Features  Lets You Monitor App Usage - 15