While I can't contest that SCons is comprehensive, I would never recommend it as a source of learning "what to do".

SCons is not idiomatic Python and it abuses things like `eval` which gives it terrible performance.

Source: I used to work for MongoDB and my full time job was to make SCons faster, which I eventually did by making it a Ninja generator (which has now been upstreamed). But the code is still pretty bad.

Using SCons however is much nicer than using make / autoconf IMO, especially now that you can farm the builds out to Ninja.