What is the URL for NuGet Gallery to access (nuget.org) from VS2010?
http://go.microsoft.com/fwlink/?LinkID=206669
That maps to: http://packages.nuget.org/v1/FeedService.svc/ but you should use the Go link to future-proof yourself.
The Microsoft Go link in the accepted answer above is an old one, the correct URL is: http://go.microsoft.com/fwlink/?LinkID=230477
This points to https://www.nuget.org/api/v2/, which is the NuGet version 2 package source feed.
I tend to use the actual URL, not the Go link anyway. As proven by the two different Go links, there is no guarantee it won't change as well, so I find it more explicit to point to the actual URL.
The Microsoft Go links are, in my opinion, a bad idea. They completely obscure the actual web URL, which defeats the purpose of HTTP addresses in the first place.
With NuGet 3, the url has changed again, it's now https://api.nuget.org/v3/index.json
.
Microsoft Docs should always list the latest feed address: Use packages from nuget.org > Enable the upstream on an existing feed.