Devlog

The format reference, and four things the research corrected

The technical layer is the reason this site exists. Writing it properly meant contradicting the project's own planning document four times.

A format gets a page here if and only if there is a written spec behind it. Everything else stays a one-line row on a hub that says so and links nowhere, because the arrow on a linked row is a promise that the click is worth making.

Writing them turned up four corrections, and the masterdoc was wrong in three of them.

What the sources actually said

.eng is documented
The planning doc listed it as undocumented. It is written up, and it spans Caesar III as well — so it earned a page instead of a row.
Caesar III saves are not ZIP
They use PKWARE DCL compression. The engine's own file is called zip.c and its function zip_compress, which is exactly the sort of name that propagates a wrong assumption for twenty years.
A .map is exactly 211,692 bytes
Fixed size, on a 162×162 grid. A number that specific is worth publishing because it is instantly checkable.
Cost and labour are not in the engine
They live in c3_model.txt, which ships with the game and which any mod may rewrite. That single fact has shaped every table on this site since.