My nearly-unused Facebook account was updated to the latest UI today (I much prefer btw) and I noticed something strange. I highlighted something for no apparent reason and some numbers showed up that aren’t there normally, at least, not when the background is white.
SO : 350.17 → A quick google doesn’t come up with anything, and it changes each time the page is refreshed. Anyone have any ideas?

Looks like some kind of debugging print statement.
SO could mean anything. Server Offset? Sort Order? Could be the number of milliseconds one particular query took to run.
Looks like I was right.
The letters are the id of the backend newsfeed server (would change during development), and the numbers are (probably) something like the time in ms took to generate the feed.