Hustle - what file are the emails stored in?

I am not looking for the ".csv" download link... I know that it is there.

I ran a 'test' email and I would like to delete that test email... as well as be able to delete future emails after I download them once, so that I do not end up with a duplicate list later down the road... I just want to add new emails to my current list as they come in, and delete the list left on the server so I can start fresh.

There must be a file somewhere on the server that emails are stored...? Right? ...so that I can edit the list myself?

Please help.
Thank you in advance.