Examine source code of savetoink

{
  "manifest_version": 2,
  "name": "savetoink",
  "description": "Save to Ink browser extension",
  "version": "0.34.3",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "activeTab",
    "contextMenus"
  ],
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{8635bdae-3d68-466f-9719-6eb9b1478ca5}"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Save to Ink"
  }
}