Hovercards makes a request for https://en.wikipedia.org/w/api.php?action=query&format=json&prop=extracts%7Cpageimages%7Crevisions&formatversion=2&redirects=true&exintro=true&exsentences=5&explaintext=true&piprop=thumbnail&pithumbsize=300&rvprop=timestamp&titles=Googol&smaxage=300&maxage=300&uselang=content

The directive explaintext tells TextExtracts to return extracts as plain text instead of limited HTML... so this is doing exactly what it should. Hovercards should probably request HTML.

In T112137#1654540, @Jdlrobson wrote:

… Hovercards should probably request HTML.

What would be the implications of doing this? Are there elements known to be in the initial excerpt that are sure to mess up the Hovercard?

Potentially. We'd need to explore it. I'd expect that we'd need to parse the output into a DOM tree and whitelist only a few images e.g. p tags, sub, and sup.

I'd suggest to implement this we'd try a different mode e.g. explainhtmlsubset and test out on mobile first.

Related to (loading plain text instead of HTML):

• T99793: Hovercard ignores math formulae
• T141766: hovercards don't show equations correctly

should we track tasks like this under one task?

merging with T152414: Previews must display useful text for the majority of articles