diff --git a/src/ol/format/MVT.js b/src/ol/format/MVT.js
index e479f30a36..954fb6d1ef 100644
--- a/src/ol/format/MVT.js
+++ b/src/ol/format/MVT.js
@@ -5,7 +5,7 @@
 
 import {inherits} from '../index.js';
 import _ol_asserts_ from '../asserts.js';
-import _ol_ext_PBF_ from 'pbf';
+import PBF from 'pbf';
 import _ol_format_Feature_ from '../format/Feature.js';
 import _ol_format_FormatType_ from '../format/FormatType.js';
 import GeometryLayout from '../geom/GeometryLayout.js';
@@ -356,7 +356,7 @@ _ol_format_MVT_.prototype.getType = function() {
 _ol_format_MVT_.prototype.readFeatures = function(source, opt_options) {
   var layers = this.layers_;
 
-  var pbf = new _ol_ext_PBF_(/** @type {ArrayBuffer} */ (source));
+  var pbf = new PBF(/** @type {ArrayBuffer} */ (source));
   var pbfLayers = pbf.readFields(_ol_format_MVT_.pbfReaders_.layers, {});
   /** @type {Array.<ol.Feature|ol.render.Feature>} */
   var features = [];
diff --git a/src/ol/renderer/canvas/VectorLayer.js b/src/ol/renderer/canvas/VectorLayer.js
index 6355eddd15..181b2e0090 100644
--- a/src/ol/renderer/canvas/VectorLayer.js
+++ b/src/ol/renderer/canvas/VectorLayer.js
@@ -7,7 +7,7 @@ import _ol_ViewHint_ from '../../ViewHint.js';
 import {createCanvasContext2D} from '../../dom.js';
 import _ol_events_ from '../../events.js';
 import EventType from '../../events/EventType.js';
-import _ol_ext_rbush_ from 'rbush';
+import rbush from 'rbush';
 import {buffer, createEmpty, containsExtent, getWidth} from '../../extent.js';
 import _ol_render_EventType_ from '../../render/EventType.js';
 import _ol_render_canvas_ from '../../render/canvas.js';
@@ -30,8 +30,7 @@ var _ol_renderer_canvas_VectorLayer_ = function(vectorLayer) {
    * Declutter tree.
    * @private
    */
-  this.declutterTree_ = vectorLayer.getDeclutter() ?
-    _ol_ext_rbush_(9) : null;
+  this.declutterTree_ = vectorLayer.getDeclutter() ? rbush(9) : null;
 
   /**
    * @private
diff --git a/src/ol/renderer/canvas/VectorTileLayer.js b/src/ol/renderer/canvas/VectorTileLayer.js
index 710f56d833..fa0b817287 100644
--- a/src/ol/renderer/canvas/VectorTileLayer.js
+++ b/src/ol/renderer/canvas/VectorTileLayer.js
@@ -7,7 +7,7 @@ import _ol_TileState_ from '../../TileState.js';
 import {createCanvasContext2D} from '../../dom.js';
 import _ol_events_ from '../../events.js';
 import EventType from '../../events/EventType.js';
-import _ol_ext_rbush_ from 'rbush';
+import rbush from 'rbush';
 import {buffer, containsCoordinate, equals, getIntersection, getTopLeft, intersects} from '../../extent.js';
 import _ol_layer_VectorTileRenderType_ from '../../layer/VectorTileRenderType.js';
 import {equivalent as equivalentProjection} from '../../proj.js';
@@ -40,7 +40,7 @@ var _ol_renderer_canvas_VectorTileLayer_ = function(layer) {
    * Declutter tree.
    * @private
      */
-  this.declutterTree_ = layer.getDeclutter() ? _ol_ext_rbush_(9) : null;
+  this.declutterTree_ = layer.getDeclutter() ? rbush(9) : null;
 
   /**
    * @private
diff --git a/src/ol/source/Raster.js b/src/ol/source/Raster.js
index 271ddfc55a..d9961145a2 100644
--- a/src/ol/source/Raster.js
+++ b/src/ol/source/Raster.js
@@ -8,7 +8,7 @@ import {createCanvasContext2D} from '../dom.js';
 import _ol_events_ from '../events.js';
 import Event from '../events/Event.js';
 import EventType from '../events/EventType.js';
-import {Processor as _ol_ext_pixelworks_Processor_} from 'pixelworks';
+import {Processor} from 'pixelworks';
 import {equals, getCenter, getHeight, getWidth} from '../extent.js';
 import _ol_layer_Image_ from '../layer/Image.js';
 import _ol_layer_Tile_ from '../layer/Tile.js';
@@ -148,7 +148,7 @@ inherits(_ol_source_Raster_, _ol_source_Image_);
  * @api
  */
 _ol_source_Raster_.prototype.setOperation = function(operation, opt_lib) {
-  this.worker_ = new _ol_ext_pixelworks_Processor_({
+  this.worker_ = new Processor({
     operation: operation,
     imageOps: this.operationType_ === _ol_source_RasterOperationType_.IMAGE,
     queue: 1,
diff --git a/src/ol/structs/RBush.js b/src/ol/structs/RBush.js
index d091f4e9f9..343105b335 100644
--- a/src/ol/structs/RBush.js
+++ b/src/ol/structs/RBush.js
@@ -2,7 +2,7 @@
  * @module ol/structs/RBush
  */
 import {getUid} from '../index.js';
-import _ol_ext_rbush_ from 'rbush';
+import rbush from 'rbush';
 import {createOrUpdate, equals} from '../extent.js';
 import _ol_obj_ from '../obj.js';
 
@@ -20,7 +20,7 @@ var _ol_structs_RBush_ = function(opt_maxEntries) {
   /**
    * @private
    */
-  this.rbush_ = _ol_ext_rbush_(opt_maxEntries);
+  this.rbush_ = rbush(opt_maxEntries);
 
   /**
    * A mapping between the objects added to this rbush wrapper