The npm library (mirrored at https://github.com/wikimedia/mediawiki-libs-LangConv, hosted on gerrit ) is imported by Parsoid/JS to support the html2html language conversion API endpoints.
This library provides the following:
* FST specs for various language variant conversions (the .foma files)
* JS tools to compile FST specs into programming-language-neutral FST representations. (.att files are the compiled representation)
* FST.js, the FST runner script that Parsoid imports to process input text through compiled programming-language-neutral FST representations in .att files
This taks to port the FST.js runner to FST.php. This ported version should be part of the wikimedia-langconv repository. But, before this code can be used in Parsoid/PHP, we need {T225023} resolved.