* The rest of the chunk is the concatenation of all the computed Bloom
filters for the commits in lexicographic order.
* Note: Commits with no changes or more than 512 changes have Bloom filters
- of length zero.
+ of length one, with either all bits set to zero or one respectively.
* The BDAT chunk is present if and only if BIDX is present.
Base Graphs List (ID: {'B', 'A', 'S', 'E'}) [Optional]