The plural forms in the limit report are wrong on frwiki, for example:
CPU time usage: 0.026 second
instead of
CPU time usage: 0.026 seconds
The limit report is localized in mediawiki-core:includes/OutputTransform/Stages/RenderDebugInfo.php with the following code:
$keyMsg = Message::newFromSpecifier( $key )->inLanguage( 'en' )->useDatabase( false );
$valueMsg = Message::newFromSpecifier( "$key-value" )
->inLanguage( 'en' )->useDatabase( false );
if ( !$valueMsg->exists() ) {
$valueMsg = new RawMessage( '$1' );
}
if ( !$keyMsg->isDisabled() && !$valueMsg->isDisabled() ) {
$valueMsg->params( $value );
$limitReport .= "{$keyMsg->text()}: {$valueMsg->text()}\n";
}
}which *ought* to force the message language to en, however local debugging with $wgLanguageCode='fr' shows that the parser target language is fr in CoreParserFunctions::plural.
This is probably a regression from Ib39d5b.