Thanks for the input. Byron Scott Jones.

Perhaps this might provide some understanding why Software is different.

Does any engineering company have two documentations on the same thing? That will violate single source of truth principle.

The challenge with Software is, the code is the ultimate truth. It itself is the documentation. If it is written well, nothing is more accurate than what the code describe.

All other documentation if needed, is just an aid and could be dated (as the code changes).

Software is there so that things can change quickly. Software code itself is the document, therefore it allows quick changes while has itself documented.

It's a different field, that all engineering though may look down on it, but getting more and more reliances on it.