Examine source code of OakBorderify

{
  "manifest_version": 2,
  "name": "Borderify",
  "version": "2.1",
  "browser_specific_settings": {
    "gecko": {
      "id": "{d2ec43ed-db3e-4001-ba88-7f9758f1975c}",
      "strict_min_version": "42.0"
    }
  },
  "description": "Adds a blue green border to all webpages matching mozilla.org.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.mozilla.org/*"
      ],
      "js": [
        "borderify.js"
      ]
    }
  ]
}