[rurban]

I recently took over GNU libredwg, which had an esp. nice codebase. The infrastructure was severely lacking, not enough warnings and probes enabled in autotools, many missing configure settings, totally bonkers unittests written by some late Google Sumner of code students, but the base architecture was excellent, with a DSL like specification language (via C macros), it was easy to extend, and works as perfectly fine documentation. readable code.

Documentation had the proper GNU framework, of course without man pages as most such GNU stuff, but this also easy to add. The other testsuite parts were also easy to add, dejagnu still rocks, gtest would have been a horror show.

GNU coding standards are a godsend.