File or folder excluded by default

I didn’t explicitly exclude any file or folder but I found some files in a folder named as .tmp.drivedownload are excluded from Kopia backup. Could someone tell me any default exclude rule by Kopia?

I found that folder is hidden in Windows Explorer.

My concern is it might exclude more files without my setup. I have a folder 1.1TB and the size on the backup destination only has 180GB. I do use compression though.

Nothing is excluded unless you define it. It is possible that some files are not included in your backup as can not be accessed by kopia.