The current message in MediaWiki core's `includes/actions/InfoAction.php` and its parameter `$1` uses [[ https://doc.wikimedia.org/mediawiki-core/master/php/classLanguage.html | `Language::formatDuration` ]]:
```
// Recent number of edits (within past 30 days)
$pageInfo['header-edits'][] = [
$this->msg( 'pageinfo-recent-edits',
$lang->formatDuration( $config->get( 'RCMaxAge' ) ) ),
$lang->formatNum( $pageCounts['recent_edits'] )
];
```
Its English translation is defined in `./languages/i18n/en.json` as `"pageinfo-recent-edits": "Recent number of edits (within past $1)",`.
On https://translatewiki.net/wiki/MediaWiki:Pageinfo-recent-edits/en people can translate that message to other languages.
"within past $1" is not a [[ https://en.wikipedia.org/wiki/Nominative_case | nominative case ]].
This makes the message untranslatable.
It looks like the fix is to split this into separate messages.