Examine source code of Flectra Debug

{
  "name": "Flectra Debug",
  "version": "5.0",
  "manifest_version": 2,
  "description": "Minimal and fast extension to toggle debug mode of Flectra",
  "short_name": "Flectra Debug",
  "browser_action": {
    "default_icon": "/images/icons/off_48.png",
    "default_title": "- Click for normal debug \n- Double click for debug with assets"
  },
  "incognito": "spanning",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "tabs"
  ],
  "icons": {
    "48": "/images/icons/off_48.png"
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Ctrl+Period"
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "pageScript.js"
  ],
  "applications": {
    "gecko": {
      "id": "flectra-debug-extension@flectrahq.ch"
    }
  }
}