Packages
Every package (sub) on Steam, newest first: what Steam sells or grants, the games and DLC inside, and its US price. “All” adds the ones the store doesn't sell: free licenses, keys, gifts and automatic grants.
What is a package?
A package (Steam also calls it a sub) is what you actually buy or get: a license that unlocks one or more apps and their downloads. A game's Standard and Deluxe editions are different packages; so is the one a Steam key activates, or the free one you get when you add a free game to your library.
Once a package is on your account, it decides which apps you may download and play.
Read from Steam continuously: every package is re-read every few hours; names and prices come from the store.