I've moved your post to Mac from the German category
The Export currently exists in a slightly different way and only as hidden feature 
If you select files in Mp3tag for Mac and copy via Cmd+C, a textual representation of the files is copied to the clipboard.
You can modify the format of this textual representation using a formatstring and the defaults command via Terminal.app
defaults write app.mp3tag.Mp3tag CopyFormat '"%album%$char(9)%track%$char(9)%title%$char(9)%artist%$char(9)%_length%$char(9)%discnumber%"'
It's a little bit nerdy, but should get the job done. Ah yes, and you can always go back to the default behavior via
defaults delete app.mp3tag.Mp3tag CopyFormat