The section clearly isn’t terminated, but it clearly is in the index.html file, first anomaly. Second, to me at least, is what is the section doing in the header.php file anyway?
First question, from your project folder, how come you end up editing the header.php file which is only available in the theme folder after the export?
Then, my first thought is that the automatically generated header is finally only a part of the page, and it is not necessarily closed, depending on where the content site is defined. I’m not surprised that Pinegrow shows an error since semantically, for HTML, this file is incorrect
Note: My first question was not asked with an inquisitive purpose, it turns out that we have often had feedback from users who had defined the project folder as the theme export folder and one can easily imagine the mess that resulted
Ok. So I then export the theme (with the given caveat that there damn all to it) which is in a completely different folder of a different physical drive and look at the header.php file there.
So this is normal.
The header.php contains the opening of the element on which the site content action is assigned and the footer.php contains the closing of this element.