LibreOffice Writer's ODF filter was always capable of remembering attributes of elements which it does not understand, so after a load and save, such attributes were not lost. But what about the rest of the file formats? InteropGrabBag is a new API we have been creating over the past few months that lets foreign filters store their unhandled attributes, so such information is not lost during such a round trip. Come and see where we are, what still needs to be done, and how you can help.