Open Radar

 
Summary:
When trying to do an automatic check and install of available downloads, Xcode shows error dialogs instead of downloading the documentation.

Steps to Reproduce:
1. Install Xcode 7.2b3.
2. Open Xcode 7.2b3.
3. Wait for documentation auto-downland dialog to pop up, and click Install, or open Preferences → Downloads and click Check and Install Now.

Expected Results:
Documentation downloads and installs.

Actual Results:
Error dialogs pop up for each item not downloaded. I included a screenshot, but here is the full text of one of the messages:

Could not download and install Xcode 7.2 Documentation. Don't know how to install package with extension  from file:///Users/zev/Library/Caches/com.apple.dt.Xcode/Downloads/com.apple.adc.documentation.Xcode-702.2.. Downloaded from {
    dependencies =     (
    );
    fileSize = 239503175;
    identifier = "com.apple.adc.documentation.Xcode";
    name = "Xcode 7.2 Documentation";
    source = "https://developer.apple.com/services-account/download?path=/Documentation/Xcode_7.2_beta_2_DocSets/03143045A.dmg";
    userInfo =     {
        ActivationPredicate = "7.2.0 >= '7.2'";
        Category = Documentation;
        IconType = IDEDownloadablesTypeDocSet;
        InstallPrefix = "/Users/zev/Library/Developer/Shared/Documentation/DocSets";
        InstalledIfAllReceiptsArePresentOrNewer =         {
            "com.apple.pkg.5.0.DevToolsDocset" = "10.9.0.0.1.1446334486";
        };
        RequiresADCAuthentication = 1;
        Summary = "My description of content";
    };
    version = "702.2";
}.

Regression:
This did not happen in previous betas of Xcode 7.2, as far as I know, and certainly not in Xcode 7.1.

Notes:
Screenshot also uploaded at http://cl.ly/dmtG