Does Steam provide extras like manuals, concept art or what not, like GOG, and if so, where do I find them?

Thanks.

For most titles, no. Some might have a document or two in their install folder, some have a link to their manual from your Steam library (see attached).

For games that do provide extras, they should be a folder in the game's installation directory called "Digital Extras", "Extras", "Content", etc. (should be specific for each game). If manuals are available, they should either be available at the game's installation directory or, alternatively, you can choose to view them by right-clicking the game in your library and selecting view Manual.

Thanks. Thanks you too.

Reminds me of Cooptional where they talk about the CD music in the extras with the instructions to burn the CD in order to listen to the music.... rather than converting it to a useful format...

See olden times

Any extras available on Shteam are bound to be as separate as possible. Example: soundtracks. Anyways, if you're going to get extras on a game purchase, that's going to be the uncommon chance of a manual, which you're linked to when you access it from the terrible client, or if you enter your game's folder and find there fully offline (heh, the implementation of opening manuals from the client sucks).

If you care about extras so much (as I do), GOG.com is the best at that department. So don't look anywhere else. Look here.

The public manuals are one great feature of Steam.

As others already said if a game on Steam has extras it's usually an extra folder in the game's install folder.

For example the Steam version of Terra Nova: Strike Force Centauri has a folder called "Bonus Content". It contains the manual, soundtrack, guide, armor schematic and quick reference card - the same extras that come with the GOG version.

Also, the manuals (for the games who have them) can be directly downloaded or read from the store page of each game. The links can be found in the bottom-right of each page (as "View the manual"). You don't need to have bought the game or have logged into Steam to download them, they're there as a public download for everyone, unlike the manuals for games on GOG...

As an example, see the store page for Skyrim: http://store.steampowered.com/app/72850/

I confirm this feature and it's great to download the manual (most of the time in your language, if it is available), even if you don't own the game.
Indeed, you can grab a french manual for a game you don't own in your Steam library whereas, sometimes, you don't have access to a french manual for your GOG game because it is english only !