The Living Spreadsheet: When a File Becomes Infrastructure Nobody Understands

[DRAFT PENDING — body content to be added]

A focused piece on the Living Spreadsheet — the years-old, formula-heavy, load-bearing file that has become read-only by accident because nobody dares modify its core logic. Explains why this is quiet key-person risk where the "key person" is a file, how to recognize one (the filename tells, the append-only growth pattern), and the constructive path: modernizing it is rebuilding the file's actual logic — including the undocumented parts — into something the company can change without holding its breath.