Examine source code of Opal - Notes

{
  "manifest_version": 2,
  "name": "Opal - Advanced Note-Taking",
  "version": "1.5.0",
  "description": "Opal: sophisticated note-taking featuring unique and advanced capabilities.",
  "icons": {
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "activeTab",
    "storage",
    "contextMenus",
    "tabs",
    "webRequestBlocking",
    "downloads"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "browser-polyfill.js",
        "js/storage.js",
        "js/notes.js",
        "js/ui.js",
        "js/main.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ],
  "browser_action": {
    "default_icon": {
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    },
    "default_popup": "popup.html",
    "default_title": "Opal - Take Notes"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "notes@opal.app",
      "strict_min_version": "91.0"
    }
  },
  "web_accessible_resources": [
    "icons/*.png"
  ]
}