GET /api/v3/klines - ignore field

I have question to documentation
When we return candle using GET /api/v3/klines, There is on position on a candle list parameters which have name “ignore”
What was in this filed and why is empty now.

Bellow info from https://github.com/binance-exchange/binance-official-api-docs/blob/master/rest-api.md
[
[
1499040000000, // Open time
“0.01634790”, // Open
“0.80000000”, // High
“0.01575800”, // Low
“0.01577100”, // Close
“148976.11427815”, // Volume
1499644799999, // Close time
“2434.19055334”, // Quote asset volume
308, // Number of trades
“1756.87402397”, // Taker buy base asset volume
“28.46694368”, // Taker buy quote asset volume
"17928899.62484339" // Ignore.
]
]

It’s a legacy field, you are safe to ignore.