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diff --git a/data/extensions/jsr@javascriptrestrictor/wrappingS-COOP-SCHEDULING.js b/data/extensions/jsr@javascriptrestrictor/wrappingS-COOP-SCHEDULING.js
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+/** \file
+ * \brief Wrappers for Cooperative Scheduling of Background Tasks API
+ *
+ * \see https://w3c.github.io/requestidlecallback/#the-requestidlecallback-method
+ *
+ *  \author Copyright (C) 2022  Libor Polcak
+ *
+ *  \license SPDX-License-Identifier: GPL-3.0-or-later
+ */
+//
+//  This program is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+/** \file
+ * \ingroup wrappers
+ *
+ * The `window.requestIdleCallback()` API can schedule background tasks
+ * such that they do not introduce delays to other high priority tasks
+ * that share the same event loop, such as input processing, animations
+ * and frame compositing.
+ *
+ * But the API leaks information about the other tasks running in the
+ * browser as it leaks information on currently scheduled tasks, vsync
+ * deadlines, user-interaction and so on.
+ *
+ * JShelter modifies the return call to:
+ *
+ * 1. Never leak the information that the call was triggered by an
+ * expired timeout.
+ * 2. Fake the information on remaining time in synchronization with the
+ * `Date.now()` wrapper. Returns up to 50% more time compared to the
+ * original value.
+ */
+
+/*
+ * Create private namespace
+ */
+(function() {
+	var wrappers = [
+		{
+			parent_object: "IdleDeadline.prototype",
+			parent_object_property: "didTimeout",
+			wrapped_objects: [],
+			helping_code: ``,
+			post_wrapping_code: [
+				{
+					code_type: "object_properties",
+					parent_object: "IdleDeadline.prototype",
+					parent_object_property: "didTimeout",
+					wrapped_objects: [],
+					/**  \brief replaces IdleDeadline.prototype.didTimeout getter
+					 */
+					wrapped_properties: [
+						{
+							property_name: "get",
+							property_value: `
+								function() {
+									return false;
+								}`,
+						},
+					],
+				}
+			],
+		},
+		{
+			parent_object: "IdleDeadline.prototype",
+			parent_object_property: "timeRemaining",
+			wrapped_objects: [
+				{
+					original_name: "IdleDeadline.prototype.timeRemaining",
+					wrapped_name: "originalF",
+				},
+			],
+			helping_code: "var lastEnd = 0;",
+			wrapping_function_args: "",
+			wrapping_function_body: `
+					let ret;
+					let now = Date.now();
+					if (now > lastEnd) {
+						let originalTimeR = originalF.call(this);
+						ret = prng() * originalTimeR * 1.5;
+						lastEnd = now + ret;
+					}
+					else {
+						ret = lastEnd - now;
+					}
+					return ret;
+				`,
+		},
+	]
+	add_wrappers(wrappers);
+})();