Does ark require C++20?
Yes. CMake requests C++20 and disables compiler extensions. See installation.
Is arknet part of this repository?
arknet is an independent header-only networking project. ark consumes its pinned release; ARKNET_SOURCE_DIR selects a local checkout for development.
Do the network tests require Python or Ruby?
No. They compile as permanent C++ doctest programs. The separate Excel configuration generator has its own requirements.
Have 100,000–200,000 simultaneous connections been validated?
That is the multi-process deployment target. Local correctness tests do not establish that capacity; see acceptance scope.