I work for the UK government. Everything my organisation does is licensed in either MIT or OGL (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/)
Developing code in the open really helps ensure you nail down your secure coding practices.
You want either, the Despecialized editions, or the Project 4k77/80/83. Despecialized is an older effort and is slightly more noisy with lower resolution whereas the Project 4k versions are what you'd expect. Both are as close to original theatrical release as you would want.