What a league folder holds

Folder What's in it
leagues/ The league's file: its name, format, divisions and options, and whether it's on this site
seasons/ Each season's file and its schedule
teams/ Each team's file, never rewritten by the simulator
rosters/ Each team's starting roster
history/ A league pack's history before the simulation, and its legends
logs/ Every match's event log, each round's post-game sequence, and the off-season's
state/ Each round's snapshot: results, standings, leaders, awards, records, rosters
db/ The event store the coverage and the statistics query
coverage/ Every piece of coverage, in every version

The logs are the record: everything else can be rebuilt from them.