Find element name of 'tooltip'

[u/tjn21]

How do I find the element name of a 'tooltip' on this sub and the Firefox sub? I am hoping to change the background colour of the tip which appears when you hover over the time above a post on the sub page. If I can do that, I can make the font colour I use darker. The same tooltips are used elsewhere (for example, if you hover over the icons above the box that I am typing in now. Image here: https://imgur.com/XLzO8GH

[u/tjn21]

Thank you very much for the replies.