In France it is: https://framagit.org/openfisca/calculette-impots-m-source-code https://framagit.org/openfisca/calculette-impots-m-source-co... The source code

In France it is: https://framagit.org/openfisca/calculette-impots-m-source-code https://framagit.org/openfisca/calculette-impots-m-source-co... The source code is actually available, written in a language called 'M'. It's been discussed a few times here on HN before: https://news.ycombinator.com/item?id=25208853 https://news.ycombinator.com/item?id=25208853 (just to link one example).