Confused by this on APFS? So you should be, as it’s complicated by features like snapshots, sparse files, and the file system itself. There’s no single figure.
I claimed (from a guess) that there might be 0.8 GB of xattrs in my Home folder. I was wildly wrong: there are actually over 3.8 GB. Here’s how xattrs are distributed.
How many bytes are there in a kilobyte, and have you heard of a kibibyte?