Reading someone else’s codebase without panicking

The four files I open first

The package manifest, the entry point, the routing table, and whichever file the last five commits touched most. Together they tell you how the project is built and where the team actually works.

Why I stopped trying to understand everything

On a large legacy codebase, full understanding is a trap. You need enough of a map to make one change safely, then the next.

A checklist

Coming in the finished version of this post.