Thanks. In my debugging attempts, I did a second export, but this time I used the file destination button, and it defaulted to my Documents folder. The filename from my initial attempt (which did not use the file destination button) definitely does not appear in my Documents folder. So, I guess when the file destination button is not used, (after a format is chosen, and text is entered in the "Export to" dialog box) the export fails silently. Is there a way to cycle back through previous status messages...
My first attempt at exporting a copy of a KeePass db, I didn't use the browse option, and typed in a filename. It didn't seem to fail, yet I can't find that file anywhere. This is on a Windows system, and I'm not much of a Windows expert. I've searched using the file explorer within my home folder, and within the folder where the kdbx file lives. This is KeePass 2.33. I specified XML, and am worried there's a plain-text copy of the database setting around somewhere.