Better argument naming and comments

src/adapters/adapter.moment.js

@@ -56,10 +56,10 @@ helpers.merge(adapter, moment ? {
 		return moment.duration(moment(max).diff(moment(min))).as(unit);
 	},
 
-	startOf: function(time, unit, opt) {
+	startOf: function(time, unit, weekday) {
 		time = moment(time);
 		if (unit === 'isoWeek') {
-			return +time.isoWeekday(opt);
+			return +time.isoWeekday(weekday);
 		}
 		return +time.startOf(unit);
 	},

src/chart.js

@@ -31,7 +31,7 @@ Chart.helpers.each(scales, function(scale, type) {
 	Chart.scaleService.registerScaleType(type, scale, scale._defaults);
 });
 
-// Built-in adapters (loaded for side effects)
+// Load to register built-in adapters (as side effects)
 require('./adapters');
 
 // Loading built-in plugins

src/core/core.adapters.js

@@ -86,6 +86,8 @@ module.exports._date = {
 	 * Returns start of `unit` for the given `timestamp`.
 	 * @param {number} timestamp - the input timestamp
 	 * @param {Unit} unit - the unit as string
+	 * @param {number} [weekday] - the ISO day of the week with 1 being Monday
+	 * and 7 being Sunday (only needed if param *unit* is `isoWeek`).
 	 * @function
 	 */
 	startOf: abstract,