I'm trying to recover text message image attachments from an LG G2. I managed to get an lbf file off of the (now non-functional) phone and followed the tutorial at https://forum.xda-developers.com/g4/help/extract-file-form-lg-backup-lbf-t3362923, and now I have a folder with a bunch files named 0.pdu, 1.pdu, 2.pdu, etc, as well as an mms_backup.xml file. For some reason, I'm having difficulty finding information on what exactly these are, and what I need to open them. Could someone point me to a program that will open these?