There's a very explicit distinction in web standards and practice between a header, and a heading. You guys seem to have called Heading a Header.

This is a pretty weird issue for me since I'm building a site using a custom semantic theme, and I have to explicitly not import the Semantic Header, and make a custom element called Header that's an actual header.

W3C terminology for reference:

https://www.w3.org/wiki/HTML/Elements/h1,_h2,_h3,_h4,_h5,_and_h6

These elements represent headings for their sections.

https://www.w3.org/wiki/HTML/Elements/header

The <header> element represents a group of introductory or navigational aids.

It would be nice if there was a real Header in semantic as well BTW.