Whenever I visit any page here on PPCG meta, to the left of the "review" link, is a small brown rectangle with a white number 4 on it, and hovering it says "4 total posts awaiting review". The link goes to https://codegolf.meta.stackexchange.com/review, but there aren't any Meta reviews currently available. (It was showing a 3 earlier and has recently changed to 4; this is all new within the past few hours.)
I remember seeing this in the past on the main PPCG site, but only very rarely; IIRC, the usual cause was a suggested edit on one of my own posts. I know it definitely doesn't come up for Meta reviews in the usual case (I've done Meta reviews before without seeing it).