FMT_MODULE flag creates two different versions of the same CMake Target `fmt::fmt` CMake, since version 3.28 supports installation of C++ Modules. It is indeed possible to install and use the module version of the library by setting `FMT_MODULE=ON` before installing. For widespread support for C++ Modules, we likely need a new CMake Target specific for modules, which can be installed alongside the regular `fmt::fmt` target and the `fmt::fmt-header-only` targets.