The starting point
A software library behaves differently from what you expected. The documentation and the examples you found do not explain your case.
The move
Open the source for the version you are running and find the function involved. An AI can guide you through it.
Why it works
The documentation summarises. The source decides. A default timeout, a condition on a value, a calculation rule: the source shows what actually happens, where the documentation says what should happen.
You do not need to read the whole project. Start from one entry point and follow it to the behaviour you care about. Today, an AI can read the code with you, explain a function line by line, and tell you where to look next. Just check it is the right version: another version’s code, or a different configuration, often explains the gap.
Outside software, the move is the same: go back to the document that sets the rule. The vendor’s terms, the spreadsheet formula, the text of the procedure, the contract. What people tell you about the rule and the rule itself are two different things.
Every time you go back to the source, you win twice: you solve your case, and you know where to look next time.
Try this
Take one precise behaviour that surprises you and write down what you expected. Give yourself fifteen minutes in the source, alone or with an AI.
Write down what you found and the exact place that shows it. Test it on a small example. If you cannot conclude, pass on what you looked at and the question that remains.
To discuss
Which recent behaviour did we understand by going back to its source?