Old post showing on home page as modified more minutes ago (by community bot) but no evidence of modification is apparent

Question

When I look at the old post it doesn’t seem as though any modification has in fact been recently made. What is the explanation for this?

Answer 1

It's been bumped by the Community bot.

Look below the voting buttons and you'll a small clock-like icon that leads to the event history / timeline. Bumped posts say:

This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.

The reasons for bumping posts may be found at this MetaSE faq