◇ Could this help me?
Yes. Understanding how data moves through a system is the fastest route into an unfamiliar codebase, and it is exactly the thing a file tree cannot show you, so generating a flow diagram and then committing it to the readme turns a one-time exercise into something the whole team keeps. The caution is not about the technique but about where the code goes: connecting a hosted platform to a private repository sends proprietary source to a third party, which is a decision for whoever owns that code rather than a convenience step. General practice.
Read this repository and produce a visualization of how data flows through it, not a file listing. Show where data enters the system, every component that transforms it along the way, and what comes out at the end, and name the actual functions and modules at each step so I can follow it in the code. Where a path branches or fails, show that too. Then write it up as a diagram and short explanation suitable for the readme, and separately list the parts of the flow you had to infer rather than read directly, so I know where to check your work.