Earlier quoted context omitted.
Yeah, sounds closer to a 5 week thing, if you know what you're doing.
Well, it is every version of RAR. Documenting the quirks of rar 1.4, 1.5, 2.0, 2.9, 3.0, 4.0, 5.0 and 7.0, multiple compression strategies, PPMd, RARVM, compression levels, encryption, multi volume support, a huge test corpus, round trips for compatibility... The spec docs are linked.
Your probably right I should read the spec but I've worked with so many brillant engineers and I am still pretty young so their must be even more. I just think the overselling of complexity is usually what makes things enterprise grade :) (if you know you know)