Examine source code of BrowserOffice :: Web Rulers

{
  "manifest_version": 3,
  "name": "__MSG_extension_name__",
  "short_name": "__MSG_extension_short_name__",
  "version": "0.1.3",
  "description": "__MSG_extension_description__",
  "author": "BrowserOffice",
  "developer": {
    "name": "BrowserOffice"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "ruler@browseroffice.bo",
      "strict_min_version": "114.0"
    }
  },
  "default_locale": "en",
  "permissions": [
    "storage",
    "activeTab",
    "tabs",
    "notifications",
    "scripting"
  ],
  "icons": {
    "48": "icons/logo.svg",
    "96": "icons/logo.svg"
  },
  "background": {
    "scripts": [
      "js/sw.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "__MSG_extension_name__",
    "default_icon": {
      "16": "icons/logo.svg",
      "32": "icons/logo.svg",
      "64": "icons/logo.svg"
    }
  },
  "options_ui": {
    "page": "options.html"
  },
  "commands": {
    "add_ruler_1": {
      "suggested_key": {
        "default": "Alt + Shift + 1"
      },
      "description": "Inserts a ruler of type 1 into current tab's document"
    },
    "add_ruler_2": {
      "suggested_key": {
        "default": "Alt + Shift + 2"
      },
      "description": "Inserts a ruler of type 2 into current tab's document"
    },
    "add_ruler_3": {
      "suggested_key": {
        "default": "Alt + Shift + 3"
      },
      "description": "Inserts a ruler of type 3 into current tab's document"
    },
    "remove_rulers": {
      "suggested_key": {
        "default": "Alt + Shift + 0"
      },
      "description": "Removes all rulers from current tab's document"
    }
  },
  "content_security_policy": {
    "extension_pages": "script-src 'self'; object-src 'self'"
  }
}