I'd like some UI element that lets me know how long it's been since I read/used a tab. I tend to open lots of tabs and then browse them as is convenient later.

I'd like some UI element that lets me know how long it's been since I read/used a tab. I tend to open lots of tabs and then browse them as is convenient later. Sometimes this means tabs get "lost" (i.e. become stale before I read them). This would let me know which tabs I might have overlooked or should close, bookmark, etc.