Get the latest tech news
Plan 9 is a uniquely complete operating system
A large contributor to the "feel" of an Operating System comes from the software it chooses to include by default. There are entire linux distributions that differentiate themselves just based on the default configured software.
On the plus side these systems get to reap the benefits of the work put in to these other projects (gnu, llvm, and so on), but this also does lead to there being some differences in design. Put in another way, if someone wanted the ability to touch every line of code (in the upstream sense), they would have to be a member of some non trivial amount of communities. It is important to highlight this difference because I think in general people are not aware of the amount of independent implementations that have been written for 9front as part of following this design.
Or read this on Hacker News