Examine source code of Tracker Blocker

{
  "manifest_version": 2,
  "name": "Tracker Blocker",
  "version": "1.2",
  "description": "It blocks trackers from popular pages from tracking you.",
  "icons": {
    "500": "icon.png"
  },
  "permissions": [
    "webRequest",
    "webRequestBlocking",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{1263003e-23b8-429b-bf8c-b3f2039b6297}"
    }
  }
}