Examine source code of Tab cleaner

{
  "manifest_version": 2,
  "version": "0.1.2resigned1",
  "name": "Tab cleaner",
  "description": "Clean up open tabs using regex",
  "homepage_url": "https://github.com/expenses/tab_cleaner",
  "permissions": [
    "tabs"
  ],
  "browser_action": {
    "browser_style": true,
    "default_title": "Tab Cleaner",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{bf11c1e1-2522-440c-b71d-5528dc92e0ee}"
    }
  }
}