Examine source code of Emotes Everywhere

{
  "manifest_version": 2,
  "name": "Emotes Everywhere",
  "version": "0.3.2",
  "description": "See custom emotes on any site.",
  "icons": {
    "128": "icons/128.png"
  },
  "permissions": [
    "storage",
    "contextMenus"
  ],
  "browser_action": {
    "default_popup": "menu.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "all_frames": true,
      "run_at": "document_end",
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "applications": {
    "gecko": {
      "id": "emoteseverywhere@epalmese.github.io",
      "strict_min_version": "57.0"
    }
  }
}