You should see the generic account in the url when clicking something. You can change the url to use your own FTP account, providing you have one, to download it.
Example, change:
ftp://ftp:any@grandis.nu/Atari/2600....
to
ftp://YourUsername:YourPassword@grandis.nu/Atari/2600....
Hm, perhaps I can change it to use your own account if you're logged in.. I'm gonna test that... Edit: Not that easy and frankly mostly annoying to get a login prompt when searching.