How to search wikicode? (source wikicode, not rendered HTML)

mediawiki

I am looking for the string lat=13.7436853 in Wikivoyage.

PROBLEM: The string is in the wikicode, not in the visible resulting HTML.
Google does not help: https://www.google.com/search?q=site:en.wikivoyage.org+13.7436853

How to search for wikicode of Wikivoyage?
Preferably without downloading a dump.

(by the way, that string is actually in the wikicode of the Rattanakosin article)

Native Wikivoyage search finds that page just fine:

Perhaps the DumpHTML Extension does what you're looking for? This tool should dump your entire wiki as HTML.

when using the new Vector skin, install the Vector extension and add this to your LocalSettings.php (after including the extension files):

$wgVectorFeatures['expandablesearch']['global'] = true;

This would expand the search box dynamically when it is focused on, but this is only a functionality of the Vector skin.