1. Scope and evidence
.dat is an extension, not a unique format identifier. This repository contains research on IGI 1 graphs.dat; the existence of a similarly named IGI 2 file does not prove that its binary structure or runtime behavior is identical.
2. What can be stated safely
The IGI 1 research notes report the byte signature CC DD EE FF, ten tagged node fields, and a value lookup rule using the signature position plus eight bytes. They also name reader routines and node criteria constants. Those notes are useful investigative evidence, but they do not provide a complete serialization grammar or establish IGI 2 compatibility.
For the researched field list, tag ambiguity, and source link, see the IGI 1 graph data notes. No APSP table, Floyd–Warshall algorithm, or IGI 2-specific record size is asserted here.
3. Verification status
IGI 2 retail samples and an IGI 2 parser/test that validates this graph layout were not available for this audit. Treat the relationship between IGI 1 and IGI 2 graph files as unresolved until checked against IGI 2 assets or binary-level implementation evidence.