OctopusVariablesDumper.cs

            const string server = "http://srvoctopus";
            const string apiKey = "API-keyhier";

            var endpoint = new OctopusServerEndpoint(server, apiKey);

            using (var client = await OctopusAsyncClient.Create(endpoint))
            {
                var repository = client.CreateRepository();

                var allProjects = await repository.Projects.GetAll();
                var variableCombinations = allProjects.SelectMany(
                    project => repository.VariableSets.Get(project.VariableSetId).Result.Variables,
                    (project, variable) => new
                    {
                        ProjectName = project.Name,
                        VariableValue = new { variable.Name, variable.Value, variable.IsSensitive, variable.Scope }
                    });

                File.WriteAllText("output.json", JsonConvert.SerializeObject(variableCombinations));
                Process.Start("output.json");
            }