The (VC++ 2019 Redist) is a set of runtime DLLs required to run applications built with Visual Studio 2019 (specifically the v142 toolset). It is not a development tool — it contains no compilers, headers, or libraries for coding. Instead, it provides the execution environment: the C and C++ standard library implementations, runtime checks, exception handling, and language support (e.g., for new , delete , STL containers, etc.).
Without it, applications compiled with VC++ 2019 will fail with errors like: microsoft visual c++ 2019 redistributable package