What is the purpose of manifest.json in a Cassandra snaphot?

Question

When a snapshot is made a manifest.json is created, what is the purpose of this file? I would have thought it contained a list of all files in the snapshot, which are:

2014-11-11 17:36:51         43 keyspace-cf-ka-1-CompressionInfo.db
2014-11-11 17:36:51         87 keyspace-cf-ka-1-Data.db
2014-11-11 17:36:51         10 keyspace-cf-ka-1-Digest.sha1
2014-11-11 17:36:51         16 keyspace-cf-ka-1-Filter.db
2014-11-11 17:36:51         25 keyspace-cf-ka-1-Index.db
2014-11-11 17:36:51       4460 keyspace-cf-ka-1-Statistics.db
2014-11-11 17:36:51        101 keyspace-cf-ka-1-Summary.db
2014-11-11 17:36:51         91 keyspace-cf-ka-1-TOC.txt
2014-11-11 17:36:51         43 keyspace-cf.field2_field1_idx-ka-1-CompressionInfo.db
2014-11-11 17:36:51         63 keyspace-cf.field2_field1_idx-ka-1-Data.db
2014-11-11 17:36:51          9 keyspace-cf.field2_field1_idx-ka-1-Digest.sha1
2014-11-11 17:36:51         16 keyspace-cf.field2_field1_idx-ka-1-Filter.db
2014-11-11 17:36:51         25 keyspace-cf.field2_field1_idx-ka-1-Index.db
2014-11-11 17:36:51       4458 keyspace-cf.field2_field1_idx-ka-1-Statistics.db
2014-11-11 17:36:51        101 keyspace-cf.field2_field1_idx-ka-1-Summary.db
2014-11-11 17:36:51         91 keyspace-cf.field2_field1_idx-ka-1-TOC.txt
2014-11-11 17:36:51         62 manifest.json

but instead it contains:

{
    "files": [
        "keyspace-cf.field2_field1_idx-ka-1-Data.db"
    ]
}

Answer 1

I contains all the sstables included in the snapshot.

https://issues.apache.org/jira/browse/CASSANDRA-6326