This package appears to have a custom/proprietary license agreement, and ProGet cannot be automatically determine the license type. You'll need to assign a license type to the URL to allow or block packages with this license.
To install Inedo.SDK from the command line, run the following command:
nuget install Inedo.SDK -Version 1.9.0-ci.35 -Source https://proget.inedo.com/nuget/NuGetLibraries/v3/index.json
To install Inedo.SDK from the Package Manager Console within Visual Studio, run the following command:
Install-Package Inedo.SDK -Version 1.9.0-ci.35 -Source https://proget.inedo.com/nuget/NuGetLibraries/v3/index.json
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageReference Include="Inedo.SDK" Version="1.9.0-ci.35" />
Defines the common API for BuildMaster, ProGet, and Otter extensions.