I was going to guess that they accused the author of copying code from Office. Was AI used in the project? Perhaps a model regurgitated copyrighted code leading to a sternly worded notice from legal...?
So AI was in use. Then the author says that following the spec alone wasn't enough to get it working, they got "active community feedback" and fed that feedback into the AI until it worked just like Word. I have to think that if there were ANY conditions under which a model might output code that Microsoft legal would threaten to sue you for, these would be them