Okay, I hadn't had the time to update to Beta 9 yet, but I assume this is still relevant (though arguably minor):
Yesterday, using Beta 8, I exported some flashcards for a friend. Chose .txt instead of .xml and the first bug I've noticed was the proposed filename: "flash.xml.txt". Pleco clings on to the .xml, if only in the file name.
Then I emailed said file to him and the name of the attachment changed to "_private_var_mobile_Applications_9342D9BF-5F47-42FD-A7E8-AE4C40AED1CC_Documents_flash.xml.txt".
The file itself was alright, so this is just about nomenclature.