That message does not support raw HTML (in fact only few messages explicitly whitelisted do, for security). Try using normal wiki external links [https://...] or use the default one.

In T228718#5357139, @MarcoAurelio wrote:

That message does not support raw HTML (in fact only few messages explicitly whitelisted do, for security). Try using normal wiki external links [https://...] or use the default one.

I see. I've submitted an edit request on enwiki. Sorry for the confusion

In T228718#5357139, @MarcoAurelio wrote:

That message does not support raw HTML (in fact only few messages explicitly whitelisted do, for security). Try using normal wiki external links [https://...] or use the default one.

A normal wikilink also didn't work - it rendered as
Logging you in to Wikimedia's other projects: ([[Help:CentralAuth|what's this?]])

Wikilinks are not supported there either - looks like the html links used to work - regression? I've deleted the enwiki page to use the mw default without links for now.

Change 859580 had a related patch set uploaded (by Stang; author: Stang):

[mediawiki/extensions/CentralAuth@master] Parse message 'centralauth-login-progress'

https://gerrit.wikimedia.org/r/859580

Change 859580 abandoned by Gergő Tisza:

[mediawiki/extensions/CentralAuth@master] Parse message 'centralauth-login-progress'

Reason:

https://gerrit.wikimedia.org/r/859580