Examine source code of Letterboxd Custom PFPs

{
  "manifest_version": 2,
  "name": "Letterboxd Custom PFPs",
  "version": "1.0.2",
  "description": "Enables the user to manually apply profile images to other letterboxd profiles, that are only visible for the user. This helps differentiate user who don't have profil icons on their profile.",
  "browser_specific_settings": {
    "gecko": {
      "id": "@letterboxd-custom-pfps",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "48": "icons/lb_c_pfp-48.png",
    "96": "icons/lb_c_pfp-96.png"
  },
  "permissions": [
    "tabs",
    "cookies",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.letterboxd.com/*"
      ],
      "js": [
        "letterboxd_custom_pfp.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "icons/lb_c_pfp-48.png",
    "default_title": "Letterboxd Custom PFPs",
    "default_popup": "popup/config.html"
  }
}