Examine source code of Ikariam Improved

{
  "manifest_version": 3,
  "name": "Ikariam Improved",
  "description": "__MSG_extension_text__",
  "author": "mrmatedev@gmail.com",
  "default_locale": "en",
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "64": "icons/icon64.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png",
      "48": "icons/icon48.png",
      "64": "icons/icon64.png",
      "128": "icons/icon128.png"
    },
    "default_popup": "popup/popup.html",
    "default_title": "Ikariam Improved"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.ikariam.gameforge.com/*"
      ],
      "js": [
        "app.js",
        "content/global_fn.js",
        "content/content.js",
        "content/feature/0_0_decimal_numbers.js",
        "content/feature/1_0_new_update.js",
        "content/feature/1_2_workshop.js",
        "content/feature/1_3_old_port_view.js",
        "content/feature/1_4_limit_buildings.js",
        "content/feature/1_5_shrine_of_olympus.js",
        "content/feature/1_6_museum_better_kga_count.js",
        "content/feature/1_7_select_all_museum.js",
        "content/feature/2_0_total_resources.js",
        "content/feature/5_0_sea_monster.js",
        "content/feature/6_0_options_color.js",
        "content/feature/7_0_options.js",
        "content/feature/7_1_do_not_disappear_science_label.js",
        "content/feature/999_0_second_reality.js",
        "content/feature/9_0_display_left_over_resources.js"
      ],
      "css": [
        "content/content.css"
      ],
      "run_at": "document_start"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "icons/*.png",
        "inject_code/*.js"
      ],
      "matches": [
        "*://*.ikariam.gameforge.com/*"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "storage"
  ],
  "host_permissions": [
    "*://*.ikariam.gameforge.com/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{81e37670-46ca-4ed1-9f34-09f0a6de1273}",
      "strict_min_version": "111.0"
    }
  },
  "background": {
    "service_worker": "background/background.js",
    "scripts": [
      "background/background.js"
    ]
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self';"
  },
  "version": "1.3.3.1"
}