Detecting appstream scheme support ; end-user-oriented "About AppStream" page (was: Re: Add "Install via AppStream" links to applications on kde.org)

[Friedrich W. H. Kossebau]

Am Sonntag, 18. Dezember 2016, 22:50:23 CET schrieb Albert Astals Cid:
> El dissabte, 17 de desembre de 2016, a les 0:17:22 CET, Friedrich W. H.
> 
> Kossebau va escriure:
> Is it possible to detect if the browser has a handler for the appstream:
> scheme and if not don't show the link at all?

At least from a quick search there is no simple querying of the supported 
protocols possible. Only saw hacks of the kind which made me try to stay out 
of web development.

I would agree only showing the link active in browsers where the protocol 
works would be nicer. I can just tell myself e.g. irc:// urls in the same box 
also have a similar fate.

@Matthias & Co: What other web pages/sites are already making use of such 
appstream links? How do they handle it?


That left aside, most people surely still have no clue what "AppStream" is.

So it could make sense to have a small note mark to the right of the 
appstream:id link for the "What the heck is Appstream" use-case, so people 
could click/tap the button and learn about AppStream (or already learn a 
little in a tooltip, though a separate note mark still is needed for discovery 
and touch UI browsing).

@Matthias: is there some distro-agnostic end-user website/page this "About 
AppStream" symbol could link to?
Only found https://www.freedesktop.org/software/appstream/docs/chap-AppStream-About.html but that is not really consumable by Sue and Joe -No-Code-Please- 
User.

Cheers
Friedrich