There's yet another proposal for embedded representation of a URL on 3rd party sites, see my previous post on Open Graph and JSON:LD.
oEmbed allows a website to display embedded content (e.g. photos or videos) when a user posts a link. Contrary to the other approaches, oEmbed requires implementation of a dedicated service endpoint (i.e. not simply some
meta HTML tags). It seems to be used by WordPress and Slack (at least the later also can do alternatives).
The act of obtaining embedded information seems to be called 'unfurling' (improving preview of an URL).
The thema can be chosen by configuring e.g.
thema: minima in
_config.yml. What theme does Github apply by default, i.e. when not explicitly setting a theme? Impossible to find out.
Also, I'd recommend using
remote_theme: jekyll/minima, so that Jekyll uses current theme code as hosted in the minima repository (or so they say).
A lot of trial-and-error goes into finding a working setup, e.g. to disable plugins (or find out which are auto-magically enabled), overriding config, etc.
Open Graph meta tags allow a web page to be interpreted/rendered nicely by social media platform, such as Twitter, Facebook (who originally created it), etc.
It's as simple as putting some
<meta property="og:xxx" content="..."/> in the
<head> of an HTML page, where
xxx can be
Another proposal to add information to web pages is JSON for Linking Data (JSON-LD). Here the focus is on machine-readable meta data for a person, place, event, product, recipe, etc. Yet another is Twitter Cards.