Today I learned about the twitter:label and twitter:data meta tags. They’re useful not just for X/Twitter/whatever but also for e.g. Slack, where they render like this for the values on this site as of earlier today:

They are numbered and go in a pair. For example, for the author and post length info in the screenshot above, I supply these tags:

<meta name="twitter:label1" content="Author" />
<meta name="twitter:data1" content="Chris Krycho" />
<meta name="twitter:label2" content="Length" />
<meta name="twitter:data2" content="About 4,000 words" />

Note the 1 and 2 in the two pairs. Does this extend out to more? Maybe! I have no idea, actually! The only documentation I have found for it is on this third-party site, which has as a top-level bullet point describing the site “⚡ 101+ Meta Tags many which have difficult to find documentation.” Sounds about right.