Examine source code of Remove css from website

{
  "name": "Remove css from website",
  "short_name": "remove css",
  "description": "Removes css from website. Remove inline styles, all styles, add custom styles.",
  "version": "0.3.5resigned1",
  "homepage_url": "https://github.com/vane/pl.vane.browser.disablecss",
  "permissions": [
    "tabs",
    "storage",
    "activeTab",
    "http://*/*",
    "https://*/*"
  ],
  "icons": {
    "16": "icons/16x16.black.png",
    "48": "icons/48x48.black.png",
    "128": "icons/128x128.black.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "remove.css.js"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "persistent": true,
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Remove css from website.",
    "default_popup": "iconstate.html",
    "default_icon": "icons/16x16.png"
  },
  "applications": {
    "gecko": {
      "id": "michal@vane.pl"
    }
  },
  "manifest_version": 2
}