It contains multiplayer_pakx which is a collection of all gta2 maps, image_pakx which is a collection of preview images for all maps that don't yet have one and game_pakx which consists of gta2 + patch + gamehunter + all kind of tools. The installer sets up everything for an immediate start.
But keep in mind that these packs are undergoing constant changes. Even when all bugs and typos are fixed it would have still to be updated everytime a map, gta2 or game hunter is updated. Therefore the packs are generated by a script that can also be adjusted to run on a server with the required permissions. If you are able to do it that way you only have to upload the tiny changes instead of the whole package files.