Why is there such a large amount of data in S3?

[mrPepcha]

Hi! I am very interested in your project. I used docker-compose from your repository to get acquainted with the project and I can't understand why so much data ends up in S3?
I'm creating a table, let's say it takes 380 Mb, but in s3 I see the volume is several times larger - 1.2 Gb. Tell me please, why is this happening? is there any setting that regulates the amount of data loading in s3?