Was checking my profile shortly after completing a game and (through Galaxy I assume) this (highlighted part of the screenshot) popped up as my current activity in the Activity Feed.

Had no idea there even was such a functionality. Has that always been there? Seems an awfully specific thing to keep track of. First time I noticed this (that it said anything else besides "Playing XYZ").

Are they pulling a Microsoft move?
Odd feature. A peculiar piece of software Galaxy is. The more you learn...

...the more you want to stay away.

Galaxy knows some old games (but not that many), for instance it knows The Lost Vikings (however the version from Blizzard website was not recognized), Alpha Storm, Corridor 7, Witchaven, Witchaven 2, Heretic (original 1994 release), Heretic 2, Hexen (several entries including duplicate), Hexen 2 but not Hexen II: Portal of Praevus. I had no idea and I'm curious as to why spent time and resourced on that, to mark them as *Owned* maybe.

Press CTRL+F and search for any game you like

This is something only certain games incorporate, including Witcher 3, called RichPresence that lets others see what part of a game you're in:
https://docs.microsoft.com/en-us/gaming/xbox-live/features/social/presence/live-presence-nav
https://docs.gog.com/sdk-friends/#richpresence

Hmm, soon enough games will be able to tell when one is on the can.

Thanks for the links. Judging by me noticing it only now, I assume that not many games on GOG have this.