Examine source code of Hikka Features

{
  "manifest_version": 2,
  "name": "Hikka Features",
  "description": "Універсальне розширення для hikka.io",
  "version": "3.1.6",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "permissions": [
    "webNavigation",
    "storage",
    "identity",
    "declarativeNetRequestWithHostAccess",
    "https://*.hikka.io/*",
    "https://*.hikka-features.pp.ua/*",
    "https://graphql.anilist.co/*",
    "https://amanogawa.space/api/*",
    "https://manga.in.ua/*",
    "https://baka.in.ua/*",
    "https://api.jikan.moe/v4/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "extension@hikka-features.pp.ua"
    }
  },
  "declarative_net_request": {
    "rule_resources": [
      {
        "id": "rules",
        "enabled": true,
        "path": "rules.json"
      }
    ]
  },
  "web_accessible_resources": [
    "/playerjs-script.js",
    "content-scripts/content.css",
    "fonts/**/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "hikka Features Settings",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://dev.hikka.io/*",
        "https://hikka.io/*"
      ],
      "js": [
        "content-scripts/content.js"
      ]
    },
    {
      "matches": [
        "https://ashdi.vip/*",
        "https://moonanime.art/*",
        "https://tortuga.tw/*"
      ],
      "all_frames": true,
      "js": [
        "content-scripts/playerjs.js"
      ]
    }
  ]
}