addressed a bunch of the Extensions changes

Octokit/Helpers/ApiExtensions.cs

@@ -7,8 +7,19 @@ using System.Threading.Tasks;
 
 namespace Octokit
 {
+    /// <summary>
+    /// Extensions for working with the <see cref="IApiConnection"/>
+    /// </summary>
     public static class ApiExtensions
     {
+        /// <summary>
+        /// Gets the API resource at the specified URI.
+        /// </summary>
+        /// <typeparam name="T">Type of the API resource to get.</typeparam>
+        /// <param name="connection">The connection to use</param>
+        /// <param name="uri">URI of the API resource to get</param>
+        /// <returns>The API resource.</returns>
+        /// <exception cref="ApiException">Thrown when an API error occurs.</exception>
         public static Task<T> Get<T>(this IApiConnection connection, Uri uri)
         {
             Ensure.ArgumentNotNull(connection, "connection");
@@ -17,6 +28,14 @@ namespace Octokit
             return connection.Get<T>(uri, null);
         }
 
+        /// <summary>
+        /// Gets all API resources in the list at the specified URI.
+        /// </summary>
+        /// <typeparam name="T">Type of the API resource in the list.</typeparam>
+        /// <param name="connection">The connection to use</param>
+        /// <param name="uri">URI of the API resource to get</param>
+        /// <returns><see cref="IReadOnlyList{T}"/> of the The API resources in the list.</returns>
+        /// <exception cref="ApiException">Thrown when an API error occurs.</exception>
         public static Task<IReadOnlyList<T>> GetAll<T>(this IApiConnection connection, Uri uri)
         {
             Ensure.ArgumentNotNull(connection, "connection");
@@ -25,6 +44,13 @@ namespace Octokit
             return connection.GetAll<T>(uri, null);
         }
 
+        /// <summary>
+        /// Gets the HTML content of the API resource at the specified URI.
+        /// </summary>
+        /// <param name="connection">The connection to use</param>
+        /// <param name="uri">URI of the API resource to get</param>
+        /// <returns>The API resource's HTML content.</returns>
+        /// <exception cref="ApiException">Thrown when an API error occurs.</exception>
         public static Task<string> GetHtml(this IApiConnection connection, Uri uri)
         {
             Ensure.ArgumentNotNull(connection, "connection");
@@ -32,7 +58,13 @@ namespace Octokit
 
             return connection.GetHtml(uri, null);
         }
-       
+
+        /// <summary>
+        /// Performs an asynchronous HTTP GET request that expects a <seealso cref="IResponse"/> containing HTML.
+        /// </summary>
+        /// <param name="connection">The connection to use</param>
+        /// <param name="uri">URI endpoint to send request to</param>
+        /// <returns><seealso cref="IResponse"/> representing the received HTTP response</returns>
         public static Task<IResponse<string>> GetHtml(this IConnection connection, Uri uri)
         {
             Ensure.ArgumentNotNull(connection, "connection");
@@ -41,6 +73,14 @@ namespace Octokit
             return connection.GetHtml(uri, null);
         }
 
+        /// <summary>
+        /// Gets the API resource at the specified URI.
+        /// </summary>
+        /// <typeparam name="T">Type of the API resource to get.</typeparam>
+        /// <param name="connection">The connection to use</param>
+        /// <param name="uri">URI of the API resource to get</param>
+        /// <returns>The API resource.</returns>
+        /// <exception cref="ApiException">Thrown when an API error occurs.</exception>
         public static Task<IResponse<T>> GetResponse<T>(this IConnection connection, Uri uri)
         {
             Ensure.ArgumentNotNull(connection, "connection");
@@ -49,6 +89,15 @@ namespace Octokit
             return connection.Get<T>(uri, null, null);
         }
 
+        /// <summary>
+        /// Gets the API resource at the specified URI.
+        /// </summary>
+        /// <typeparam name="T">Type of the API resource to get.</typeparam>
+        /// <param name="connection">The connection to use</param>
+        /// <param name="uri">URI of the API resource to get</param>
+        /// <param name="cancellationToken">A token used to cancel the GetResponse request</param>
+        /// <returns>The API resource.</returns>
+        /// <exception cref="ApiException">Thrown when an API error occurs.</exception>
         public static Task<IResponse<T>> GetResponse<T>(this IConnection connection, Uri uri, CancellationToken cancellationToken)
         {
             Ensure.ArgumentNotNull(connection, "connection");

Octokit/Helpers/AuthorizationExtensions.cs

@@ -3,6 +3,9 @@ using System.Threading.Tasks;
 
 namespace Octokit
 {
+    /// <summary>
+    /// Represents operations to simplify triggering the authorization flow
+    /// </summary>
     public static class AuthorizationExtensions
     {
         /// <summary>

Octokit/Helpers/HttpClientExtensions.cs

@@ -7,6 +7,9 @@ namespace Octokit
 {
     public static class HttpClientExtensions
     {
+        /// <summary>
+        /// OBSOLETE
+        /// </summary>
         [Obsolete("This will be removed in a future release")]
         public static Task<IResponse<T>> Send<T>(this IHttpClient httpClient, IRequest request)
         {

Octokit/Helpers/IApiPagination.cs

@@ -14,6 +14,12 @@ namespace Octokit
     /// </remarks>
     public interface IApiPagination
     {
+        /// <summary>
+        /// Paginate a request to asynchronous fetch the results until no more are returned
+        /// </summary>
+        /// <typeparam name="T">Type of the API resource to get.</typeparam>
+        /// <param name="getFirstPage">A function which generates the first request</param>
+        /// <param name="uri">The original URI (used only for raising an exception)</param>
         Task<IReadOnlyList<T>> GetAllPages<T>(Func<Task<IReadOnlyPagedCollection<T>>> getFirstPage, Uri uri);
     }
 }

Octokit/Helpers/ModelExtensions.cs

@@ -2,6 +2,11 @@
 
 namespace Octokit
 {
+    // TODO: this is only related to SSH keys, we should rename this
+
+    /// <summary>
+    /// Extensions for working with SSH keys
+    /// </summary>
     public static class ModelExtensions
     {
 #if NETFX_CORE
@@ -10,6 +15,10 @@ namespace Octokit
         static readonly Regex sshKeyRegex = new Regex(@"ssh-[rd]s[as] (?<data>\S+) ?(?<name>.*)$", RegexOptions.Compiled);
 #endif
 
+        /// <summary>
+        /// Extract SSH key information from the API response
+        /// </summary>
+        /// <param name="sshKey">Key details received from API</param>
         public static SshKeyInfo GetKeyDataAndName(this SshKey sshKey)
         {
             Ensure.ArgumentNotNull(sshKey, "sshKey");
@@ -20,6 +29,11 @@ namespace Octokit
             return (match.Success ? new SshKeyInfo(match.Groups["data"].Value, match.Groups["name"].Value) : null);
         }
 
+        /// <summary>
+        /// Compare two SSH keys to see if they are equal
+        /// </summary>
+        /// <param name="key">Reference SSH key</param>
+        /// <param name="otherKey">Key to compare</param>
         public static bool HasSameDataAs(this SshKey key, SshKey otherKey)
         {
             Ensure.ArgumentNotNull(key, "key");

Octokit/Helpers/ParameterAttribute.cs

@@ -2,10 +2,21 @@
 
 namespace Octokit.Internal
 {
+    /// <summary>
+    /// Indicate to the serializer that this property or value 
+    /// has a different representation when being serialized to JSON
+    /// </summary>
     [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
     public sealed class ParameterAttribute : Attribute
     {
+        /// <summary>
+        /// The key to use in place of the property's name
+        /// </summary>
         public string Key { get; set; }
+
+        /// <summary>
+        /// The name to use in place of the enum's value
+        /// </summary>
         public string Value { get; set; }
     }
 }

Octokit/Helpers/SerializeNullAttribute.cs

@@ -2,6 +2,10 @@
 
 namespace Octokit.Internal
 {
+    /// <summary>
+    /// Indicate to the serializer that this property or field
+    /// should be included, even when currently set to `null`
+    /// </summary>
     [AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)]
     public sealed class SerializeNullAttribute : Attribute
     {