Just look at the time stamp and repeat it out loud, you will remember it, works every time

An extension should be able to do this so search for those. But it would probably make sense to have such extension be specific to some particular website, because lots of websites have videos which exist for purposes other than the “main content of that page” and trying to remember all such things would be pretty wasteful.

I watch a lot of stuff; I keep a note page on where I left off. Might be days later, there it is. But yeah, it’d be useful.