What is bus gtfs-rt protobuf extension 1006?

[sm12...@gmail.com]

Some of the records in the MTA Bus Vehicle gtfs-rt feed have a data entry with the extension 1006. Here's an example of such an entry using the decode_raw option:

2 {
  1: "MTA NYCT_8403"
  4 {
    1 {
      1: "QV_C2-Weekday-064600_MISC_170"
      3: "20220824"
      5: "Q83"
      6: 1
    }
    2 {
      1: 0x4222cc86
      2: 0xc29386cf
      3: 0x42ff4b95
    }
    5: 1661353456
    7: "500182"
    8 {
      1: "MTA NYCT_8403"
    }
    1006 {
      1: 39
    }
  }

What's it's meaning?

I tried to use the google registry but got a bad link.

Thanks in advance.

Steve