Examine source code of FFBE Sync v2

{
  "manifest_version": 3,
  "name": "FFBE Sync v2",
  "version": "1.1.2",
  "description": "FFBE Sync v2",
  "icons": {
    "128": "icon128.png"
  },
  "background": {
    "scripts": [
      "./static/js/background.js"
    ]
  },
  "action": {},
  "host_permissions": [
    "https://lapis340v-gndgr.gumi.sg/*",
    "https://v890-lapis.gumi.sg/*",
    "https://www.facebook.com/*"
  ],
  "permissions": [
    "identity",
    "scripting"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "ffbe-sync-v2@svitkona.xyz"
    }
  }
}