• load.php -> ResourceLoader::respond -> .. -> ResourceLoader::preloadModuleInfo -> ResourceLoaderWikiModule::preloadTilteInfo
• We then iterate over the relevant modules, and only for those that have getDB() return the local database do we actually preload title info.
• It is unexpected that, despite us intentionally ignoring the foreign database, a connection is still being opened.

<https://github.com/wikimedia/mediawiki-extensions-GlobalCssJs/blob/6f228b5f5046b011fddc5d97e487dcaa59447106/ResourceLoaderGlobalModule.php#L77-L83

return wfGetLB( $this->wiki )->getConnectionRef( DB_SLAVE, [], $this->wiki );

...
			$module = $rl->getModule( $name );
			if ( $module instanceof self ) {
				$mDB = $module->getDB();
				// Subclasses may disable getDB and implement getTitleInfo differently
				if ( $mDB && $mDB->getWikiID() === $db->getWikiID() ) {