New factions without replacing vanilla ones, .exe patch

From the engine's perspective, there's no difference, but with .h5u it's slightly more convenient to separate the core and content. The mod's core, other frameworks (like NCF) can be placed as .pak in data, while content mods (directly new factions) are stored separately in usermods. This way, at least you won't accidentally delete something you shouldn't (each faction is its own file, and constantly adding/removing factions is intended as a standard procedure) + the conflict resolver mentioned in the overview works specifically with content mods; if everything were in data, the resolver would need to be complicated with filters to specifically search for content .pak files.