No. The swift stdlib is the API that is available by default without any import statements (consisting of the Swift, _Concurrency, and _StringProcessing modules

No. The swift stdlib is the API that is available by default without any import statements (consisting of the Swift, _Concurrency, and _StringProcessing modules). The runtime is a separate library that programs do not explicitly interact with; calls into the runtime are implicitly generated by the compiler when necessary to perform tasks like allocation or retain/release.