Wikipedia:Wikipedia Signpost/Templates/Signpost-article-header-v2/doc

Usage
This template allows you to insert the top header of a signpost article, and it also starts the actual article's canvas. It limits the width of all this to 80 ems and uses viewport relative margins on the left and right.

You always need to balance the usage of this template with a call to Wikipedia Signpost/Templates/Signpost-article-end-v2.

The type of article will be displayed on the line above the title according to the subpage name, so create e.g. as Wikipedia:Wikipedia_Signpost/YYYY-MM-DD/Op-ed if the title should be "Op-ed".

Styles and classes
(incomplete) There are five non-displaying metadata fields: These pass through the params for piccy metadata; even though they aren't displayed on the article page, they make the text appear so that it can be searched or extracted by external applications.

If the  param is embedded, there's also a hidden 1px embed of it, which causes it to register as in-use (and avoid Commons deletions).