save file suffix

[Kevin HaleBoyes]

I'm very, very new to GnuCash.  All I've done so far is use
the druid to create my list of accounts.  I haven't added
transactions or really gone beyond these simple beginnings.

After I used the druid I wanted to save my results and was
prompted to enter a filename.  There was no automatic suffix
generated and I didn't know what suffix to give the file.

Is the file saved in a standard format with a "well-known"
suffix?  What suffix should I use?

Thanks for your help.
Kevin.