This is less of a TIL and more of a “I am writing this down in the hope that I don’t need to Google it again when I next run into it” (as are a lot of these TILS).
According to people on the internet who know more than me, the proper hierarchy for semantic HTML tags is as follows.
<html> <body> <header>Header Stuff</header> <main> Main is a per page component that should contain the main (get it...) content of the page but not the stuff that is repeated on every page e.g. Nav and Footer </main> <footer>Footer stuff</footer> </body></html>