A file opens with its table, whatever it holds: a value that breaks its column's type is named where it is written, never coerced.
Each column's name, then its type after a colon, then its formula after an equals sign.
One line a row. A cell holds a value, or a value and the formula that computed it.
A write stores what it changes, and leaves every other byte as it was read.
A stored value its formula no longer gives is named, never overwritten.
Two versions merge row by row, and a computed value is never a conflict.