In general, memory allocated by the Go runtime is garbage collected, yes. When the garbage collector runs, there isn't really any difference between user and runtime goroutines anymore. But the garbage collector itself doesn't created garbage implicitly.
Go is a language that does not expose stack vs. heap allocation as a primitive to the programmer. Memory is allocated in the best place possible, preferably on the stack, but if that is not possible it is allocated on the heap. But in the runtime we need to control the generation of garbage, so runtime code is compiled with a switch that forbids implicit heap allocations (code won't compile if it requires transparent heap allocations). Heap memory is allocated by calling a function like runtime.mallocgc. However, this memory is garbage collected just like everything else (e.g. there is no free).
Go is a language that does not expose stack vs. heap allocation as a primitive to the programmer. Memory is allocated in the best place possible, preferably on the stack, but if that is not possible it is allocated on the heap. But in the runtime we need to control the generation of garbage, so runtime code is compiled with a switch that forbids implicit heap allocations (code won't compile if it requires transparent heap allocations). Heap memory is allocated by calling a function like runtime.mallocgc. However, this memory is garbage collected just like everything else (e.g. there is no free).