Capybara Cursor ★ Custom Cursor for Chrome™

The content script is injected into every page (including subframes) at `document_start`, meaning it executes before the page's own scripts and DOM have loaded. Combined with `all_frames: true`, this gives the extension the earliest possible hook into every website the user visits, which is broader than necessary for a simple cursor-override tool that only injects CSS.

{  "content_scripts": [    {      "all_frames": true,      "js": [        "cursorcontent.js"      ],      "matches": [        "*://*/*"      ],      "run_at": "document_start"    }  ]}

On installation the extension silently opens a tab to an external domain (`yowgames.com`) with UTM tracking parameters, and registers an uninstall callback URL that phones home when the extension is removed. While common in adware-style extensions, this allows the publisher to track installation and removal events per user without explicit disclosure.

chrome.runtime.onInstalled.addListener(function(details) {  if (details.reason === "install") {    chrome.tabs.create({      url: "https://yowgames.com/capybara-cursor-%e2%98%85-custom-cursor-for-chrome/?utm_source=install&utm_medium=link&utm_campaign=bg&utm_content=install"    });  }});chrome.runtime.setUninstallURL(  "https://yowgames.com/capybara-cursor-%e2%98%85-custom-cursor-for-chrome/?utm_source=Uninstall&utm_medium=link&utm_campaign=bg&utm_content=Uninstall");

The popup page (which runs in the privileged `chrome-extension://` origin) loads a stylesheet from Google Fonts over the network. Every time the popup is opened this makes an outbound request that reveals the user's IP address and browser fingerprint to Google's CDN, without any opt-in from the user.

<link href="https://fonts.googleapis.com/css2?family=Nunito:wght@400;600;700&display=swap" rel="stylesheet">

A MutationObserver is attached to `document.documentElement` with `subtree: true` on every page the user visits, watching for iframe/frame additions. While used here only to reapply cursor CSS, running a persistent DOM watcher across the entire document tree of every website has a non-trivial performance footprint and represents broader page monitoring than a cursor extension strictly requires.

const observer = new MutationObserver(function(mutations) {  if (mutations.some(mutation =>      mutation.type === 'childList' &&      (mutation.addedNodes.length > 0 || mutation.removedNodes.length > 0) &&      Array.from(mutation.addedNodes)      .some(node => node.nodeName === 'IFRAME' || node.nodeName === 'FRAME')    )) {    if (cursorData) {      applyCursor(cursorData);    }  }});observer.observe(document.documentElement, {  childList: true,  subtree: true});