I would much rather this be when tab close rather than browser close.

I rarely close my browser except for updates, or when I'm spe cifcally taking advantage of delete on exit. However, delete on tab close would be dreamy.

I don't really want it to be an extension. I don't like the power given to extensions, so the less I use the better. Sorry decent extension devs, for me the bad guys have tarnished the trust to just not want to use any.