What links here
From PCGamingWiki, the wiki about fixing PC games
Game content which can extend the percentage of playtime substantially. Including and not limited to: large story campaigns, a large number of new maps or levels, expanded gameplay, etc. In pre-digital distribution age, expansion packs were separate boxed products that may or may not require the original game to install and run. As a rule of thumb we would consider DLCs or bundles of DLCs in packs that extend the main game's playtime 'substantially' or by 40% or more.
XCOM: Enemy Unknown
's expansion is XCOM: Enemy Within, which substantially adds new content and gameplay mechanics.
's multiple DLCs contain substantial new campaigns which are each individually large enough to constitute an expansion pack
Expansive Expansions (Expansion Packs)