This should be a no-brainer. Storing source code at GitHub would facilitate rapid development of addons by the open source community with more checks and balances, better testing, and swifter performance. And if you took it a step further by permitting development of the core by the open source community Fusion 360 could be developed much faster and with far fewer bugs and security vulnerabilities. Fixing existing bugs would also be more streamlined. This would result in a huge savings in development costs, a more prominent web presence, and lower subscription rates for the consumer. It's a win-win for everyone.
