Examine source code of osu! Mutual finder

{
  "browser_specific_settings": {
    "gecko": {
      "id": "osu-mutual-finder@extension",
      "strict_min_version": "128.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "description": "Scan a Mutualify user page and find accounts that mention mutuals. by sheepex_",
  "host_permissions": [
    "https://mutualify.stanr.info/*",
    "https://osu.ppy.sh/*",
    "https://flagcdn.com/*",
    "https://osu-mutuals.noahcraft01.workers.dev/*"
  ],
  "icons": {
    "16": "icons/icon128.png",
    "48": "icons/icon128.png",
    "128": "icons/icon128.png"
  },
  "manifest_version": 3,
  "name": "osu! Mutual finder",
  "permissions": [
    "tabs",
    "scripting",
    "storage",
    "identity"
  ],
  "sidebar_action": {
    "default_icon": {
      "16": "icons/icon128.png",
      "48": "icons/icon128.png",
      "128": "icons/icon128.png"
    },
    "default_panel": "popup.html",
    "default_title": "osu! Mutual finder"
  },
  "version": "1.1.0"
}