I ask a few focusing questions: "What does the business do, what do the users care about, and what value does this system add for those users?" "What 'things'

I ask a few focusing questions: "What does the business do, what do the users care about, and what value does this system add for those users?" "What 'things' does this system involve?" Print out the DB schema + classes to see all of the entities represented in the system. "What are the things this system does?" Read the unit tests. They describe the intended behavior + the minimal context required for that behavior. "How do I see output for the changes I make when I work?" Ask a few of the other devs what their feedback loop looks like during development. Then I make a copy of the repo and comment the shit out of it for myself. I summarize the existing code, and include any observations, thoughts, whatever. One more: I keep a text file with a list of "activating questions" prior to any of this, which I continually add to, and write answers in. I use this to batch inquiries for other devs, who I set up 20-minute sessions with to answer my questions, so I don't pepper them continually with interruptions.