Within Google Search, the company is experimenting with a clock/timer symbol on the site links. If you’ve landed at this page from a Google search, the purpose of this icon is likely to make itself known.
For example, Mordy Oberstein saw this occurrence on Twitter and said, “Seeing Google exhibiting an icon subsequent to sitelinks indicating you have already seen that particular web page.” One of his screenshots can be seen here:

Seeing Google exhibiting an icon subsequent to sitelinks indicating you already seen that particular web page cc: his royal SERPness Mr. Rusty aka @rustybrick pic.twitter.com/kd3GulWPjb
— Mordy Oberstein ???????? (@MordyOberstein) October 7, 2022
It’s not uncommon for Google to experiment with alternative icons in Sitelinks or even to add photos in Sitelinks.