tl;dr: Buttons that link you to a Discourse post
Continuing the discussion from Make activating an Account Gmail-compatible:
So anyway, Github emails come with some extra html that makes action buttons appear on GMail and in Inbox, possibly even elsewhere but I'm not aware of any. They look like this:
<div itemscope itemtype="http://schema.org/EmailMessage">
<div itemprop="action" itemscope itemtype="http://schema.org/ViewAction">
<link itemprop="url" href="https://github.com/syncthing/syncthing/issues/1519#issuecomment-88384950"></link>
<meta itemprop="name" content="View Issue"></meta>
</div>
<meta itemprop="description" content="View this Issue on GitHub"></meta>
</div>
<div itemscope itemtype="http://schema.org/EmailMessage">
<div itemprop="action" itemscope itemtype="http://schema.org/ViewAction">
<link itemprop="url" href="https://github.com/BuildAPC/BuildAPC-docs/pull/46#issuecomment-88387645"></link>
<meta itemprop="name" content="View Pull Request"></meta>
</div>
<meta itemprop="description" content="View this Pull Request on GitHub"></meta>
</div>
So in what I could figure out, the itemprop name and the description are not visible at all on GMail but the corresponding string do appear if you Ctrl+F for them on the page source.
Inbox is even weirder as the itemprop="description"
string is visible on the Issue email but not on the Pull Request one. Possibly caused by the mention.
Would be pretty if Discourse would use this schema/code/whatever too!