The Translate extension has a useful feature to add non-translated "variables" with the <tvar> syntax. However this doesn't seem to work when used for CentralNotice messages, instead the raw code is always displayed.
|Open||Feature||None||T34482 CentralNotice should respect language fallbacks|
|Open||Feature||None||T38591 Use the Translate extension in CentralNotice (tracking)|
|Open||None||T87448 Can't use Translate extension's variables feature in CentralNotice|
|Open||None||T116235 [Epic] CentralNotice translation should move closer to MediaWiki i18n standards and the code cleaned up|