I didn't set it, but I would like to request an option to omit it. It didn't used to be in the information box. I think it doesn't apply to a lot of games, and I suspect most games that have this set didn't do so intentionally. It's the default setting if you fill out that page, but it's probably gray initially until the Save button is pressed. (It might be a new thing because I don't remember ever seeing it in the information box before today.)
Edited: Based on the description it sounds like somehow it's a measurement of how long people played it in an actual session, and I'd assume a "session" is a sitting, and not "Time it takes to reach an objective (complete a level, a run, etc.)".
No, not a measurement, but the creator's own estimation. It doesn't even show up at all in the More Information box unless the creator sets it in the game metadata, which is on another tab and can't even be done until the game page is saved as a draft at least. So please double-check your project settings, because this option has been there for years.
There's no opt-out option for that field. If you fill out that page (to indicate the game uses a gamepad for instance) then it automatically fills out that field, which then puts it in the information box (like it or not.) Just use your brain and ask if every game on that page actually had somebody intentionally set them to say they last 3 seconds.... only Rock Scissor Paper lasts 3 seconds... think about it before you speak.