diff --git a/platform/commonUI/formats/src/FormatProvider.js b/platform/commonUI/formats/src/FormatProvider.js
index c5690ca8aa..e72dd52b68 100644
--- a/platform/commonUI/formats/src/FormatProvider.js
+++ b/platform/commonUI/formats/src/FormatProvider.js
@@ -63,6 +63,28 @@ define([
      * @returns {string} the text representation of the value
      */
 
+    /**
+     * Provides access to `Format` objects which can be used to
+     * convert values between human-readable text and numeric
+     * representations.
+     * @interface FormatService
+     */
+
+    /**
+     * Look up a format by its symbolic identifier.
+     * @param {string} key the identifier for this format
+     * @returns {Format} the format, or `undefined` if no such format
+     *                   is known.
+     */
+
+    /**
+     * Provides formats from the `formats` extension category.
+     * @constructor
+     * @implements {FormatService}
+     * @memberof platform/commonUI/formats
+     * @param {Array.<function(new : Format)>} format constructors,
+     *        from the `formats` extension category.
+     */
     function FormatProvider(formats) {
         var formatMap = {};
 
diff --git a/platform/commonUI/formats/src/UTCTimeFormat.js b/platform/commonUI/formats/src/UTCTimeFormat.js
index 43028d7e97..f20e1cade9 100644
--- a/platform/commonUI/formats/src/UTCTimeFormat.js
+++ b/platform/commonUI/formats/src/UTCTimeFormat.js
@@ -37,6 +37,14 @@ define([
         ];
 
 
+    /**
+     * Formatter for UTC timestamps. Interprets numeric values as
+     * milliseconds since the start of 1970.
+     *
+     * @implements {Format}
+     * @constructor
+     * @memberof platform/commonUI/formats
+     */
     function UTCTimeFormat() {
     }