This is invoked as such:
From Template:Signpost archive:
{{Wikipedia:Signpost/Template:Signpost-header|[[Wikipedia:Wikipedia Signpost/Archives|← Back to Archives]]|{{date|{{{2}}}|dmy}}|[[Wikipedia:Wikipedia Signpost|View Latest Issue]]}}From article pages, like Wikipedia:Wikipedia Signpost/2023-08-01/Humour:
{{Wikipedia:Signpost/Template:Signpost-header|||}}From Wikipedia:Wikipedia Signpost:
{{Wikipedia:Signpost/Template:Signpost-header|{{Str left|{{Wikipedia:Wikipedia Signpost/Templates/Issue|2}}|9}}|{{date|{{Wikipedia:Wikipedia Signpost/Templates/Issue|1}}|dmy}}|{{Str right|{{Wikipedia:Wikipedia Signpost/Templates/Issue|2}}|10}}}}In general, as you can see above, it takes three unnamed parameters:
{{{1}}}, for text on the left{{{2}}}, for text in the center{{{3}}}, for text on the rightIt summons a TemplateStyles from Wikipedia:Wikipedia Signpost/Templates/Signpost-header/styles.css and uses it to style and create the Signpost header.
It uses these divs and these classes, contained in this order:
signpost-header nomobile noprint (container div, no content in the div itself)
signpost-header-heading (File:Signpost2.svg)
signpost-header-subheadings (container div, no content in the div itself)
signpost-header-volume (volume number, on left, e.g. "Volume 19")signpost-header-issue (issue number, on right, e.g. "Issue 16")signpost-header-date (date of issue, in center, e.g. "15 August 2023")signpost-header-subsubheadings (empty div -- this can be used for whatever nonsense by the frontend)Note that signpost-header-volume, signpost-header-issue and signpost-header-date can actually just be whatever random stuff -- and, in fact, some templates (like {{Signpost archive}}) do call the header template with stuff other than volumes and issues in those locations.
Note again -- very importantly -- the following.
That's a totally different template that exists for some reason (?)
