How can I tell what HTML formatting has been applied?

Once I have applied some HTML formatting, such as H1 or H2, the text turns green, so I know that formatting exists. However, how do I find out exactly what formatting has been applied after the fact? Selecting the green highlighted text and then looking in the HTML menu does not put a checkmark by a header style, for example, as I would expect. This becomes a problem when I have formatted a page using some headers, but then need to go back and add similarly styled items later - I don’t remember what I used in the past, and it becomes trial and error (or copy/paste) to try and recreate the styles. Was hoping there was an easier way. Thanks!

One way is to look at the HTML source… e.g. you’d see Header (<H2>, <H4> etc) tags where you’d applied them as formatting.