[henesy]

One of the best parts of the Plan 9 system is that all of the kernel/command/library source is on hand and readily available to consult at any given time.

Jointly, an important detail is that the complexity of said source is kept to a sane minimum and general style trends mean that most, if not all, of the source is formatted similarly and legibly. The system is so compact that you can keep most of the system source in your head at one time if you really need to.

[henesy]

A fun tidbit from the Plan 9 compilers only really able to be found by reading the source: https://groups.google.com/forum/#!msg/comp.os.plan9/uMF7A4gk...