All my hobby coding in C++ makes use of modules.
Visual C++ and clang, alongside MSBuild and CMake/ninja.
As for ecosystem fragmentation, it has been the same old story since WG14 and WG21 exist, each compiler and platform is their own snowflake of what they actually support.
> All my hobby coding in C++ makes use of modules.
Do you have an example (of yours or others) that you could link?
I've been trying to get this up and running myself, but can't seem to whisper the right CMake prayers.