The description is a little vague and hand-wavey. Here's a concrete example:
A lot of Wikipedia sites have scripts embedded in the wikitext which automatically generate or transform information on a page, e.g. automatically performing unit conversions to generate text like "I would walk 500 miles (804.67 km)", performing date math to automatically generate and update a person's age based on their birthdate, or querying structured data from Wikidata [1] to display in an infobox. One example of these scripts is the {{convert}} [2] template on the English Wikipedia.
Initially, these scripts were written in MediaWiki template logic [3], and were maintained individually on each wiki. This quickly proved unmaintainable, and some of those scripts were rewritten in Lua using the Scribunto extension [4], but these were still per-wiki, and there were frequently issues where different wikis would copy scripts from each other and introduce their own incompatible features.
The WikiFunctions project is an attempt to centralize development of these scripts, much like how Wikimedia Commons [5] centralizes hosting of freely licensed images and other media.
[1]: https://wikidata.org/
[2]: https://en.wikipedia.org/wiki/Template:Convert
[3]: https://www.mediawiki.org/wiki/Help:Extension:ParserFunction...
[4]: https://www.mediawiki.org/wiki/Extension:Scribunto
[5]: https://commons.wikimedia.org/
A lot of Wikipedia sites have scripts embedded in the wikitext which automatically generate or transform information on a page, e.g. automatically performing unit conversions to generate text like "I would walk 500 miles (804.67 km)", performing date math to automatically generate and update a person's age based on their birthdate, or querying structured data from Wikidata [1] to display in an infobox. One example of these scripts is the {{convert}} [2] template on the English Wikipedia.
Initially, these scripts were written in MediaWiki template logic [3], and were maintained individually on each wiki. This quickly proved unmaintainable, and some of those scripts were rewritten in Lua using the Scribunto extension [4], but these were still per-wiki, and there were frequently issues where different wikis would copy scripts from each other and introduce their own incompatible features.
The WikiFunctions project is an attempt to centralize development of these scripts, much like how Wikimedia Commons [5] centralizes hosting of freely licensed images and other media.
[1]: https://wikidata.org/
[2]: https://en.wikipedia.org/wiki/Template:Convert
[3]: https://www.mediawiki.org/wiki/Help:Extension:ParserFunction...
[4]: https://www.mediawiki.org/wiki/Extension:Scribunto
[5]: https://commons.wikimedia.org/