On macOS applications can mark transient and cache files with an extended attribute com.apple.metadata:com_apple_backup_excludeItem to inform time machine that those files and directories should not be backed up. Since the application developers have much better idea about what files need and need not be preserved this approach works better than centralized exclusion list.
Some notable third party backup tools (Duplicacy, Arq, CrashPlan) support exclusion by that attribute as well.
Kopia should too. This cuts down drastically on the need for the user to write (and maintain!) elaborate exclusion patters.