diff --git a/src/ol/source/TileArcGISRest.js b/src/ol/source/TileArcGISRest.js
index c23020c6a4..0f0bc4b0bf 100644
--- a/src/ol/source/TileArcGISRest.js
+++ b/src/ol/source/TileArcGISRest.js
@@ -10,6 +10,47 @@ import TileImage from '../source/TileImage.js';
 import {hash as tileCoordHash} from '../tilecoord.js';
 import {appendParams} from '../uri.js';
 
+/**
+ * @typedef {Object} Options
+ * @property {ol.AttributionLike} [attributions] Attributions.
+ * @property {number} [cacheSize=2048] Cache size.
+ * @property {null|string} [crossOrigin] The `crossOrigin` attribute for loaded images.
+ * Note that you must provide a `crossOrigin` value if you are using the WebGL renderer
+ * or if you want to access pixel data with the Canvas renderer.  See
+ * {@link https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image}
+ * for more detail.
+ * @property {Object.<string,*>} [params] ArcGIS Rest parameters. This field is optional. Service defaults will be
+ * used for any fields not specified. `FORMAT` is `PNG32` by default. `F` is `IMAGE` by
+ * default. `TRANSPARENT` is `true` by default.  `BBOX, `SIZE`, `BBOXSR`,
+ * and `IMAGESR` will be set dynamically. Set `LAYERS` to
+ * override the default service layer visibility. See
+ * {@link http://resources.arcgis.com/en/help/arcgis-rest-api/index.html#/Export_Map/02r3000000v7000000/}
+ * for further reference.
+ * @property {ol.tilegrid.TileGrid} [tileGrid] Tile grid. Base this on the resolutions,
+ * tilesize and extent supported by the server.
+ * If this is not defined, a default grid will be used: if there is a projection
+ * extent, the grid will be based on that; if not, a grid based on a global
+ * extent with origin at 0,0 will be used.
+ * @property {ol.ProjectionLike} projection Projection.
+ * @property {number} [reprojectionErrorThreshold=0.5] Maximum allowed reprojection error (in pixels).
+ * Higher values can increase reprojection performance, but decrease precision.
+ * @property {ol.TileLoadFunctionType} [tileLoadFunction] Optional function to load a tile given a URL.
+ * The default is
+ * ```js
+ * function(imageTile, src) {
+ *   imageTile.getImage().src = src;
+ * };
+ * ```
+ * @property {string} [url] ArcGIS Rest service URL for a Map Service or Image Service. The
+ * url should include /MapServer or /ImageServer.
+ * @property {boolean} [wrapX=true] Whether to wrap the world horizontally.
+ * @property {number} [transition] Duration of the opacity transition for rendering.  To disable the opacity
+ * transition, pass `transition: 0`.
+ * @property {Array.<string>} urls ArcGIS Rest service urls. Use this instead of `url` when the ArcGIS
+ * Service supports multiple urls for export requests.
+ */
+
+
 /**
  * @classdesc
  * Layer source for tile data from ArcGIS Rest services. Map and Image
@@ -20,8 +61,7 @@ import {appendParams} from '../uri.js';
  *
  * @constructor
  * @extends {module:ol/source/TileImage~TileImage}
- * @param {olx.source.TileArcGISRestOptions=} opt_options Tile ArcGIS Rest
- *     options.
+ * @param {module:ol/source/TileArcGISRest~Options=} opt_options Tile ArcGIS Rest options.
  * @api
  */
 const TileArcGISRest = function(opt_options) {
diff --git a/src/olx.jsdoc b/src/olx.jsdoc
deleted file mode 100644
index 499f6c0878..0000000000
--- a/src/olx.jsdoc
+++ /dev/null
@@ -1,39 +0,0 @@
-/**
- * @namespace olx
- */
-
-/**
- * @namespace olx.control
- */
-
-/**
- * @namespace olx.format
- */
-
-/**
- * @namespace olx.interaction
- */
-
-/**
- * @namespace olx.layer
- */
-
-/**
- * @namespace olx.parser
- */
-
-/**
- * @namespace olx.render
- */
-
-/**
- * @namespace olx.source
- */
-
-/**
- * @namespace olx.style
- */
-
-/**
- * @namespace olx.tilegrid
- */
diff --git a/tasks/t.js b/tasks/t.js
deleted file mode 100644
index 3e09af3421..0000000000
--- a/tasks/t.js
+++ /dev/null
@@ -1,187 +0,0 @@
-const fs = require('fs');
-const util = require('util');
-const path = require('path');
-
-const readFile = util.promisify(fs.readFile);
-const writeFile = util.promisify(fs.writeFile);
-const externs = path.resolve(__dirname, '../externs');
-
-function parse(source) {
-  const length = source.length;
-
-  let index = 0;
-  const IN_CODE = 'in code';
-  const IN_COMMENT = 'in comment';
-
-  function next() {
-    const char = source.charAt(index);
-    ++index;
-    return char;
-  }
-
-  function scanLine() {
-    let char = next();
-    let line = '';
-    while (index < length && char !== '\n') {
-      line += char;
-      char = next();
-    }
-    return line;
-  }
-
-  let state = IN_CODE;
-  const blocks = [];
-  let comment;
-  while (index < length) {
-    const line = scanLine();
-    if (state === IN_CODE) {
-      if (line === '/**') {
-        state = IN_COMMENT;
-        comment = '';
-      }
-      continue;
-    }
-
-    // in a comment
-    if (!line) {
-      continue;
-    }
-
-    if (line !== ' */') {
-      comment += line + '\n';
-      continue;
-    }
-
-    // comment is done
-    const code = scanLine();
-    if (code.startsWith('olx')) {
-      blocks.push({code, comment});
-    }
-    state = IN_CODE;
-  }
-  return blocks;
-}
-
-function processParam(name, comment) {
-  const IN_DESCRIPTION = 'in description';
-  const IN_TYPE = 'in type';
-  const DONE = 'done';
-
-  const lines = comment.split('\n');
-  lines.pop(); // ends with newline
-  let description = '';
-  let type;
-  let state = IN_DESCRIPTION;
-  lines.forEach(line => {
-    if (state === DONE) {
-      throw new Error(`Extra comment after @api for param ${name}:\n${comment}`);
-    }
-
-    if (!(line.startsWith(' * ') || line === ' *')) {
-      throw new Error(`Unexpected comment start for param ${name}:\n${comment}`);
-    }
-
-    if (line.indexOf('@type ') === 3) {
-      state = IN_TYPE;
-      if (type) {
-        throw new Error(`Duplicate type for param ${name}:\n${comment}`);
-      }
-      type = line.slice(9);
-      return;
-    }
-
-    if (line.indexOf('@api') === 3) {
-      state = DONE;
-      return;
-    }
-
-    if (state === IN_DESCRIPTION) {
-      if (type) {
-        throw new Error(`Description after type for param ${name}:\n${comment}`);
-      }
-      description += line.slice(3) + '\n';
-      return;
-    }
-
-    type += line.slice(3) + '\n';
-  });
-
-  return {name, type, description};
-}
-
-function getName(name) {
-  if (!name.startsWith('olx.')) {
-    throw new Error(`Unexpected name: ${name}`);
-  }
-  return name.slice(4).replace(/\./g, '_');
-}
-
-function processBlock(block, data) {
-  const name = getName(block.code.slice(0, -1));
-
-  const protoStart = name.indexOf('_prototype_');
-  if (protoStart > 0) {
-    const parentName = name.slice(0, protoStart);
-    const childName = name.slice(protoStart + 11);
-    if (!(parentName in data)) {
-      throw new Error(`No parent for ${block.code}`);
-    }
-    const param = processParam(childName, block.comment);
-    data[parentName].params.push(param);
-    return;
-  }
-
-  if (block.comment.indexOf('@typedef') === -1) {
-    if (block.comment.indexOf('Namespace.') === -1) {
-      throw new Error(`Unexpected comment for ${block.code}`);
-    }
-    return;
-  }
-
-  data[name] = {
-    name,
-    comment: block.comment,
-    params: []
-  };
-}
-
-function processBlocks(blocks) {
-  const data = {};
-  blocks.forEach(block => processBlock(block, data));
-  return data;
-}
-
-function format(data) {
-  let source = '';
-  for (const name in data) {
-
-    // add the @typedef
-    source += `\n/**\n * @typedef {Object} ${name}\n`;
-
-    const params = data[name].params;
-    if (!params.length) {
-      throw new Error(`No params for ${name}`);
-    }
-
-    params.forEach(param => {
-      const description = param.description.replace(/\n$/, '').split('\n').join('\n * ');
-      source += ` * @property ${param.type} ${param.name} ${description}\n`;
-    });
-    source += ' */\n\n';
-  }
-  return source;
-}
-
-async function main() {
-  const source = String(await readFile(path.join(externs, 'olx.js')));
-  const blocks = parse(source);
-  const data = processBlocks(blocks);
-  const output = format(data);
-  await writeFile(path.join(externs, 'xol.js'), output);
-}
-
-if (require.main === module) {
-  main().catch(err => {
-    process.stdout.write(`${err.stack}\n`, () => process.exit(1));
-  });
-}