Yes, you can update master labels of Custom Links and Buttons using the "Quick Update Translations" app. Follow these steps:

  • Open the "Quick Update Translations" app and navigate to the "Quick Update Translations" tab.
  • From the "Select Entity to Translate" section, choose "Custom Links/Buttons".
  • This will open the "Update Custom Link/Button Translations" page.
  • In the "Select Object" section, select the object for which you want to update the custom Links and Buttons labels 
  • In the "Select Links/Buttons" dropdown, select the specific custom link/button for which you want to update the master labels.
  • Under "Select Language", choose the languages for which you want to add or update translations.
  • Click on the "Fetch Custom Link/Button Translations" button.
  • The page will display a table with the selected custom links/buttons.
  • Update the master labels and translations as per your requirements in the table.
  • Click on the "Save Link and Button  Translations" button to save your changes.

By following these steps, you can easily update custom links/button labels and their translations in different languages, ensuring that your Salesforce instance is fully localized and user-friendly for users of various language preferences.