Please rename this module from 'Workflow extras' to 'Workflows extras'. (mind the 's') - If not in the file names, then at least in the project name.
This current name is confusing, since it implies that it builds upon/requires the contrib Workflow → module (alive and kicking since 2003, with currently 7.700 reported installations), while it requires the core Workflows module. (Again, mind the 's').
Thanks,
Fixed
2.0
Miscellaneous