How to delete IOS Files from my mac?

My IPhone 6S is dying and today I wanted to create a backup of it on my Mac.

So I followed the instructions and nearly at the end of backup process - my mac ran a warning, which said that mac didn't have enough memory to make a backup, BUT it had taken 95,93 GB of macbook memory by iOS Files (I suspect these files are undone backup uploaded somewhere).

In order to clean that undone backup I checked every system file on macbook - everything is clear (no files in the library, no backups in iTunes), but now I have not enough memory to make a backup even after I've cleaned up everything I don't need on mac, except these files!

Can you, please, explain how or help me with deleting those files, which I can't even see in my root folders?