Examine source code of Themis Extension

{
  "name": "Themis Extension",
  "description": "Making Themis bar prep a bit easier (Unofficial extension)",
  "version": "0.0.1",
  "manifest_version": 3,
  "permissions": [
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "options.html",
    "default_icon": {
      "16": "/images/icon16.png",
      "32": "/images/icon32.png",
      "48": "/images/icon48.png",
      "128": "/images/icon128.png"
    }
  },
  "icons": {
    "16": "/images/icon16.png",
    "32": "/images/icon32.png",
    "48": "/images/icon48.png",
    "128": "/images/icon128.png"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": false
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.themisbar.com/learners/index.php*"
      ],
      "js": [
        "content-script.js"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "script.js"
      ],
      "matches": [
        "https://www.themisbar.com/*"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "themis-extension-firefox@wunter8.dev"
    }
  }
}