User blog comment:FishTank/Introducing Vanguard, Wikia's Newest Volunteer Team/@comment-26169720-20160822162644/@comment-26402117-20160822191050

If I read it right, Zambiealex is describing his coding ability - tis relevant.

Parser functions are a form of wikitext code and relate to the infobox's syntax. They are used in PIs by placing them in the  tag as shown here. As a note, the fields do not appear when undeclared or left empty so there is no need for using the  function to replicate this functionality.

Yat's link contains a full list of parser functions with usage.