Examine source code of localpocket

{
  "manifest_version": 3,
  "name": "LocalPocket",
  "description": "Local-first Pocket alternative — save pages to plain files you own.",
  "version": "0.0.1",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "storage",
    "activeTab",
    "contextMenus",
    "scripting"
  ],
  "action": {
    "default_title": "Save to LocalPocket",
    "default_icon": {
      "16": "icon/16.png",
      "32": "icon/32.png",
      "48": "icon/48.png",
      "96": "icon/96.png",
      "128": "icon/128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "localpocket-app@null102.dev",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "open_in_tab": true,
    "page": "options.html"
  }
}