You can actually do this. The label is a salesforce “Custom Label” so you can add a new translation value (in English) that will override the package default. Here is how.
- In Salesforce Setup - go to Create - Custom Labels.
- Find the label for Mass Update Selected Rows. Don’t Edit the label - put push the link on the name to get the detail page.
- Add a new "Local Translation / Override using the language you want.
Custom Label Detail Page:
Resulting Table…