owzthat.epr is a eprom card that contains the files:
- OWZTHAT.B: Tokenised basic file
- OWZTHAT.EXE: Plain text file ready to be executed from the Filter (just added the #B characters at the beginning)
- INFO.PPD: Pipedream file which explains the included files

More info:

https://spectrumcomputing.co.uk/entry/38120/Cambridge_Z88/Owzthat

