FIXME: SHOULD REALLY BE DATA/PLUGINS/FILE/BLOBS.
The blobs directory is used for the storage of data objects that are too large to be stored in Berkeley DB. Files in this directory have names generated by fakefs, usually consisting of Hash values (see section 7.5.4) encoded as pairs of hexadecimal digits, split into some number of subdirectories.
See section 9.2.5 for details on directory hashing.