User blog comment:Rappy 4187/Technical Update: April 27, 2016/@comment-9380534-20160428134412/@comment-24473195-20160429093444

"@Dessamator StringFunctions is not installed at Wikia. The functionality was moved to ParserFunctions years ago, and the former promptly uninstalled assuming it ever came to Wikia at all."

Indeed, those functions appear to have been moved in their original state to the parser function extension. It is quite likely that they still retained the underlying code, and all the drawbacks that come with it. Apparently, some parser functions like #pad are actually a security risk, because depending on the configuration they may facilitate DoS attacks[1].

Here's a quote by one of the developers who seemed to have disabled it for the WMF:

Enable string functions. + * + * Set this to true if you want your users to be able to implement their own + * parsers in the ugliest, most inefficient programming language known to man: + * MediaWiki wikitext with ParserFunctions. + * + * WARNING: enabling this may have an adverse impact on the sanity of your users. https://phabricator.wikimedia.org/T8455#110965 Here's undeniable proof that it DID affect users adversely:

http://fallout.wikia.com/wiki/Template:Infobox?oldid=2146434

A 200 KB Infobox with a crazy mix of string functions and parser functions.