Tabnabbing module fails because source.js is missing

SET version: 8.1.3

When using: Website Attack Vectors -> Web Jacking Attack Method -> Custom Import

SET throws:

[Errno 2] No such file or directory: 'src/webattack/tabnabbing/source.js'

The file is referenced in: src/webattack/tabnabbing/tabnabbing.py

but source.js does not exist in the repository or installation.