There are 2 MAME rom sets,

Torrent zip and Torrent 7zip

tzip is over 50 GB, t7zip is around 32 GB.

Each rom is separate in the tzip set, the t7zip set each clone rom is merged with the parent rom archive so thats a tad confusing but it reads/runs exactly as it normally should.

tzip set is easier to update/downgrade, t7zip takes way longer because of the compression method.