Of all the possible things that might be expected, why is a copy of the source code the thing that stands out. If it’s on my machine why shouldn’t I expect exc

Of all the possible things that might be expected, why is a copy of the source code the thing that stands out. If it’s on my machine why shouldn’t I expect excellent documentation, or configuration support, or build help, or features as I request them? What makes the source code and only the source code the exact thing I should expect?