ThreeCatsWink: there is no extras option for any game???
I don't know why you're talking about "any game" when you only own one.
The Extras tab -- to the left of the Play/Install button -- for all games* lists the offline installer, as well as patches, if there are any. For games that support the feature, the cloud saves backup is also listed.
Some games will include certain goodies for free. To check if that's the case for your game, click the "More" button next to the Play/Install button, and select "View in store". The store page usually has details on any included goodies.
You can also open
your library in a web browser, and click your game. If there are any extras, they'll be listed on the right side.
If you continue having problems, it would help if you'd attach a screenshot of the issue.
* except GWENT: The Witcher Card Game, which is online-only multiplayer and therefore has no offline installer.