Here is a list of all files with brief descriptions:

class.Api.php
core/Cache.class.php
core/CommonsenseOAuthClient.class.php
core/Diagnostics.class.php
core/Library.class.php
core/OAuthConsumer.class.php
core/OAuthDataStore.class.php
core/OAuthError.class.php
core/OAuthException.class.php
core/OAuthProvider.class.php
core/OAuthRequest.class.php
core/OAuthResponse.class.php
core/OAuthSignatureMethod.class.php
core/OAuthToken.class.php
core/OAuthUtil.class.php
core/ResponseCodes.class.php
core/signature/OAuthSignatureMethodHmacSha1.class.php
core/signature/OAuthSignatureMethodPlainText.class.php
core/signature/OAuthSignatureMethodRsaSha1.class.php
objects/Data.php
objects/Device.php
objects/Environment.php
objects/Group.php
objects/Notification.php
objects/Sensor.php
objects/Service.php
objects/Trigger.php
objects/User.php
test/TestMetatags.php