The theme seems to be TIME, where each of the theme answers contain a circled letter which together spell TIME, and the clues are all “See circles”. Thus, the clues for each theme answer are “Time”, leading to answers JAILSEN(T)ENCE, FOURTHD(I)MENSION, POPULAR(M)AGAZINE, and TEST(E)RSSHOUT – all alternative meanings of “time”. The circled letters are also positioned in a straight vertical line.
The puzzle comes with a note:
> Shortz Says: This is the first puzzle I can remember in which the theme answers are clued by the grid itself. Everything is very smoothly worded, too. An amazing feat.
Maybe this kind of playful theming wasn’t as common 20+ years ago, warranting a note on what today would seem like a pretty standard theme. But given the effusiveness of Shortz’ note, I was expecting a little more aha! in the reveal, so I’m wondering if there’s some extra layer of theme or pun or something I’m missing.