What is the scope dictionary in the ASGI protocol and what does it contain?

# Inspecting the scope in an ASGI app
async def app(scope, receive, send):
    print(scope["type"])      # "http", "websocket", or "lifespan"

    if scope["type"] == "http":
        print(scope["method"])          # "GET", "POST", etc.
        print(scope["path"])            # "/api/users"
        print(scope["query_string"])    # b"page=1&limit=10"
        print(scope["headers"])         # list of (name, value) byte tuples
        print(scope["client"])          # ("127.0.0.1", 54321) - IP and port
        print(scope["server"])          # ("127.0.0.1", 8000)
        print(scope["scheme"])          # "http" or "https"
        print(scope["root_path"])       # e.g. "/api/v1" if --root-path is set
        print(scope["http_version"])    # "1.1"

    elif scope["type"] == "websocket":
        print(scope["path"])            # WebSocket path
        print(scope["headers"])         # Upgrade headers
        print(scope["subprotocols"])    # Requested sub-protocols

    elif scope["type"] == "lifespan":
        pass  # handle startup and shutdown events