BigQuery COMPRESSED storage tier?

When I was exploring BigQuery's public dataset today and the details shown from BigQuery information schema I noticed some of the BigQuery tables use a storage tier called "COMPRESSED". This is quite interesting because the logical bytes of the table and the billable bytes of the table are significantly different which mean the cost on querying those tables will be significantly cheaper. Anyone seen this before or know how to make use of it? 

But this doesn't seem to be documented anywhere and all tables I've created seem to either have Active or Long Term but I've not seen anything labelled as COMPRESSED. 

The following query got me these information

SELECT
*
FROM
`bigquery-public-data.london_bicycles.INFORMATION_SCHEMA.PARTITIONS`
 
And some of the details I retrieved as as follows and the logical type is about 6 times bigger in size for table cycle_hire
Row table_catalog table_schema table_name partition_id total_rows total_logical_bytes total_billable_bytes last_modified_time storage_tier  
 
Row table_catalog table_schema table_name partition_id total_rows total_logical_bytes total_billable_bytes last_modified_time storage_tier

Row

table_catalog

table_schema

table_name

partition_id

total_rows

total_logical_bytes

total_billable_bytes

last_modified_time

storage_tier

 

1

bigquery-public-data

london_bicycles

cycle_stations

null

785

78650

30982

2022-09-09 21:02:32.345000 UTC

COMPRESSED

 

2

bigquery-public-data

london_bicycles

cycle_hire

null

24369201

2784394803

469461272

2019-05-08 11:21:52.696000 UTC

COMPRESSED

0 1 1,187
1 REPLY 1

You would be able to directly request more details about what this storage tier means if you create a support case with Google Cloud.