Format of keys and values in bitcore [CLOSED]

[Shawshank]

I am trying to understand the format of keys and values in the bitcore LevelDB database.

I have extracted this record:

{"key":"txa2-1XPTgDRhN8RFnzniWCddobD9iKZatrvH4-9998728386554-faa2cb087a2b0c5e2c898f713ebd77762afb7088a2bd0c720615a6b2efc54eb1-1",
"value":"1000000:1:1:42f4500dec4c6f8cd41337767bdf7e2caa48c153ae2114334a645ac927d03766:289:1273862997"}

For the "key" name:
What does the number 9998728386554 mean?
What does the last number 1 at the end mean?

For the "value" name:
What does the pair :1:1: mean?
What does the number 289 mean?

EDIT: More precisely, the LevelDB database is created by insight-api, which uses bitcore.

[Shawshank]

I managed to get the answer after reviewing the source code. For the record (pun intended) 

For the "key" name:
What does the number 9998728386554 mean?

1e13-Unix timestamp, i.e. reverse timestamp, to be able to order it backwards quickly.

What does the last number 1 at the end mean?

vout order in the transaction

For the "value" name:
What does the pair :1:1: mean?
What does the number 289 mean?

This info is relevant for version of insight older than v0.2. For version 0.2 and older spents are obtained with  txs-.