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DaveBentfield / Visual distinction for owned Games on GOG.com 

// ==UserScript==
// @name           Visual distinction for owned Games on GOG.com
// @namespace      https://openuserjs.org//users/DaveBentfield
// @description    Adds more visual distinction for owned Games on GOG.com
// @include        https://www.gog.com/*
// @exclude        https://www.gog.com/upload/*
// @exclude        https://www.gog.com/forum/*
// @exclude        https://www.gog.com/wishlist/*
// @require        https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js
// @version        0.0.2
// @copyright      2018, DaveBentfield (https://openuserjs.org//users/DaveBentfield)
// @license        MIT
// ==/UserScript==

$(window).on('DOMSubtreeModified', function() {
  $(".product-tile:has(.product-tile__labels--in-library)").css("opacity", "0.25")
});