Interesting... I wonder why they would need that..
What about DLC like soundtracks or art books?

I see your point... well, seems OSTs are very much installable :).

Here's an example:
https://api.gog.com/products/1076210813?expand=downloads,expanded_dlcs,description,screenshots,videos,related_products,changelog

P.S.: Oh, but it seems at least movies, which are ironically registered as a "game", are not installable.

Well, that's the only case I could see it being useful for... otherwise it seems redundant and just doing the same thing as the game_type field..

Give it some time, maybe the GOGBears are still thinking about its usage :).

it definitely does.
or at least it did last time I checked
given that the two examples you found are the most recent( I think?) released game bundles, it might mean that they have changed the way they handle these game packs.

curios how Galaxy downloads the installer then ...
guess we need to wait until someone who owns these games sniffs things out :)

Very interesting... do you have any idea what Galaxy is using as a user agent for its connections?

(And to think I was setting my user agent to mimic a regular Firefox config in my scripts in order to avoid fingerprinting...)

"GOGGalaxyClient/1.2.23.4 (Windows 7 6.1 (Build 7601: Service Pack 1)IA32)", but anything starting with GOGGalaxyClient works.

Mwhahaha, thanks :P. I feel another full product id range scan coming along.

Have fun and don't forget to share :D

Ehm, Huston we have a problem. Tried the Galaxy user agent you provided as well as some gibberish and still can't see a thing. Was that all you changed when you got to pry though the veil of GOGBear?

Then try authorizing with a token. Maybe that's what did it.

Nope, that didn't work either. I've got other stuff I can try as well, at least you pointed me in the right direction, no worries :).

This is what has worked for me reliably so far:

1. Set the user agent to something GOGGalaxyClient
2. Authorize the call using a token
3. Use the fully expanded URL with locale set to en-US:
https://api.gog.com/products/2134842136?expand=downloads,expanded_dlcs,description,screenshots,videos,related_products,changelog&locale=en-US

Once the product has been requested successfully, you can drop the expand query again and it will continue to work. After so many months of dealing with the GOG API, it still surprises me which incredible inconsistencies they manage to introduce. Seriously, WTF?

Yeah, well... ok, I'll give it another shot next week. Though are you sure I don't need to also throw a pinch of salt over my right shoulder for everything to work? :P