Examine source code of Swello

{
  "name": "__MSG_appName__",
  "version": "2.0.2",
  "manifest_version": 2,
  "description": "__MSG_appDescription__",
  "icons": {
    "16": "images/16x16.png",
    "24": "images/24x24.png",
    "36": "images/36x36.png",
    "48": "images/48x48.png",
    "128": "images/128x128.png"
  },
  "web_accessible_resources": [
    "http://localhost:8080",
    "scripts/*.*",
    "https://clocktweets.com/*"
  ],
  "default_locale": "fr",
  "background": {
    "scripts": [
      "scripts/background.js"
    ]
  },
  "permissions": [
    "tabs",
    "http://*/*",
    "https://*/*",
    "contextMenus"
  ],
  "content_scripts": [
    {
      "matches": [
        "http://*/*",
        "https://*/*"
      ],
      "exclude_matches": [
        "https://clocktweets.com/dashboard/*"
      ],
      "js": [
        "scripts/contentscript.js"
      ],
      "run_at": "document_end",
      "all_frames": false
    }
  ],
  "browser_action": {
    "default_title": "Swello",
    "default_icon": {
      "16": "images/16x16.png",
      "24": "images/24x24.png",
      "36": "images/36x36.png"
    }
  }
}