diff --git a/src/ol/format/feature.js b/src/ol/format/feature.js
index 37a05cc26c..6a4f30b2c9 100644
--- a/src/ol/format/feature.js
+++ b/src/ol/format/feature.js
@@ -34,13 +34,6 @@ ol.format.Feature = function() {
 };
 
 
-/**
- * @abstract
- * @return {Array.<string>} Extensions.
- */
-ol.format.Feature.prototype.getExtensions = function() {};
-
-
 /**
  * Adds the data projection to the read options.
  * @param {Document|Node|Object|string} source Source.
diff --git a/src/ol/format/geojson.js b/src/ol/format/geojson.js
index 3c6993a0fb..f93175eb6d 100644
--- a/src/ol/format/geojson.js
+++ b/src/ol/format/geojson.js
@@ -57,14 +57,6 @@ ol.format.GeoJSON = function(opt_options) {
 ol.inherits(ol.format.GeoJSON, ol.format.JSONFeature);
 
 
-/**
- * @const
- * @type {Array.<string>}
- * @private
- */
-ol.format.GeoJSON.EXTENSIONS_ = ['.geojson'];
-
-
 /**
  * @param {GeoJSONGeometry|GeoJSONGeometryCollection} object Object.
  * @param {olx.format.ReadOptions=} opt_options Read options.
@@ -334,14 +326,6 @@ ol.format.GeoJSON.GEOMETRY_WRITERS_ = {
 };
 
 
-/**
- * @inheritDoc
- */
-ol.format.GeoJSON.prototype.getExtensions = function() {
-  return ol.format.GeoJSON.EXTENSIONS_;
-};
-
-
 /**
  * Read a feature from a GeoJSON Feature source.  Only works for Feature or
  * geometry types.  Use {@link ol.format.GeoJSON#readFeatures} to read
diff --git a/src/ol/format/igc.js b/src/ol/format/igc.js
index 212b16b2c4..34af4fcf71 100644
--- a/src/ol/format/igc.js
+++ b/src/ol/format/igc.js
@@ -41,14 +41,6 @@ ol.format.IGC = function(opt_options) {
 ol.inherits(ol.format.IGC, ol.format.TextFeature);
 
 
-/**
- * @const
- * @type {Array.<string>}
- * @private
- */
-ol.format.IGC.EXTENSIONS_ = ['.igc'];
-
-
 /**
  * @const
  * @type {RegExp}
@@ -84,14 +76,6 @@ ol.format.IGC.HFDTE_RECORD_RE_ = /^HFDTE(\d{2})(\d{2})(\d{2})/;
 ol.format.IGC.NEWLINE_RE_ = /\r\n|\r|\n/;
 
 
-/**
- * @inheritDoc
- */
-ol.format.IGC.prototype.getExtensions = function() {
-  return ol.format.IGC.EXTENSIONS_;
-};
-
-
 /**
  * Read the feature from the IGC source.
  *
diff --git a/src/ol/format/kml.js b/src/ol/format/kml.js
index 206f2569c0..49583d6075 100644
--- a/src/ol/format/kml.js
+++ b/src/ol/format/kml.js
@@ -99,14 +99,6 @@ ol.format.KML = function(opt_options) {
 ol.inherits(ol.format.KML, ol.format.XMLFeature);
 
 
-/**
- * @const
- * @type {Array.<string>}
- * @private
- */
-ol.format.KML.EXTENSIONS_ = ['.kml'];
-
-
 /**
  * @const
  * @type {Array.<string>}
@@ -1646,14 +1638,6 @@ ol.format.KML.STYLE_MAP_PARSERS_ = ol.xml.makeStructureNS(
     });
 
 
-/**
- * @inheritDoc
- */
-ol.format.KML.prototype.getExtensions = function() {
-  return ol.format.KML.EXTENSIONS_;
-};
-
-
 /**
  * @param {Node} node Node.
  * @param {Array.<*>} objectStack Object stack.
diff --git a/src/ol/format/osmxml.js b/src/ol/format/osmxml.js
index 289a3b2366..4ccc4ddf72 100644
--- a/src/ol/format/osmxml.js
+++ b/src/ol/format/osmxml.js
@@ -35,22 +35,6 @@ ol.format.OSMXML = function() {
 ol.inherits(ol.format.OSMXML, ol.format.XMLFeature);
 
 
-/**
- * @const
- * @type {Array.<string>}
- * @private
- */
-ol.format.OSMXML.EXTENSIONS_ = ['.osm'];
-
-
-/**
- * @inheritDoc
- */
-ol.format.OSMXML.prototype.getExtensions = function() {
-  return ol.format.OSMXML.EXTENSIONS_;
-};
-
-
 /**
  * @param {Node} node Node.
  * @param {Array.<*>} objectStack Object stack.
diff --git a/src/ol/format/topojson.js b/src/ol/format/topojson.js
index dcab6fcd86..c0c4a5b263 100644
--- a/src/ol/format/topojson.js
+++ b/src/ol/format/topojson.js
@@ -40,13 +40,6 @@ ol.format.TopoJSON = function(opt_options) {
 ol.inherits(ol.format.TopoJSON, ol.format.JSONFeature);
 
 
-/**
- * @const {Array.<string>}
- * @private
- */
-ol.format.TopoJSON.EXTENSIONS_ = ['.topojson'];
-
-
 /**
  * Concatenate arcs into a coordinate array.
  * @param {Array.<number>} indices Indices of arcs to concatenate.  Negative
@@ -201,14 +194,6 @@ ol.format.TopoJSON.readMultiPolygonGeometry_ = function(object, arcs) {
 };
 
 
-/**
- * @inheritDoc
- */
-ol.format.TopoJSON.prototype.getExtensions = function() {
-  return ol.format.TopoJSON.EXTENSIONS_;
-};
-
-
 /**
  * Create features from a TopoJSON GeometryCollection object.
  *