Yes, you can update translations of managed package custom labels. Here are the steps to do so:
- Go to the "Quick Update Translations" tab.
- Select "Custom Labels" from the "Select entity to translate" dropdown menu.
- This will open the "Update Custom Labels Translations" page.
- In the "Select Custom Labels" section, search for the managed package labels that you want to update translations for, and select them.
- Under "Select Language", choose the languages for which you want to add or update translations.
- Click the "Fetch Custom Label Translations" button.
- The page will display a table with the selected labels and languages. You can update the translations directly in this table.