There is a distinction between being able to access the source code, and a tool giving it to you without any context of the underlying license it is governed by.
Good teams still document these. Amazon is apparently a leading example where the documents are considered the source of truth.
However many organisations have limited technical leadership enforcing quality, and management layers not willing to invest in these assets.
Unfortunately some 'modern' practices are being interpreted to make the processes like Agile the most important thing, and reducing the importance of things like code/system quality and knowledge management.
Edgar, you might be interested to know there are significant problems with the big javascript files being downloaded on Linux for Office365, particularly for WordOnline.
We've done similar experiments and proven it to be again based on your own user-agent detection, since normally they will take 30-60 seconds to load, causing the UI to essentially lock up and fail, when faking the agent-user to something else will work around it.
Multiple attempts at contacting Microsoft support come back with its not supported.
Its the Web... pretty sure you can build things without breaking them for Linux.