I installed 3.1.0RC2 at 11.07.2014.
From that date it creates files like:
in the "store" directory.
Up to now: 2,9 GiB of these files.
Inside these archives, i have some or many of the board attachments.
- go to a topic with attachments
- press --> tools --> download all attachments
- the packed-files will be created in "store"