Handling APFS/HFS+

I'm concerned with backing up an APFS or HFS+ disk to a ZFS formatted NAS.  I am considering my options, including using `dar` over `ssh`.

After some research, I see that on MacOS, standard unix tools like rsync and tar have been updated to handle the complicated metadata structure (Extended Attributes, including variable numbers of variable length forks; Finder data; and other metadata).  So they will work if backing up to another Apple formatted disk, but not to "real" unix formats; and the standard unix tools will not be able to handle the output.  I also see that Apple's NFS has been updated with the capability of transferring in the "AppleDouble" format [1] and that their SMB will transfer as something called "Alternate Data Streams" (ADS) [2],  both of which can be stored to non-Apple disks.  (Though I am not clear what the requirements are on the receiving end.  If someone knows, please tell me.)

So my question is, could someone describe how `dar` backs up APFS/HFS+ files, including what kind of format it uses to store those files in its archive?  AppleDouble?  ADS?  Something else?

Also, if I were to then try to copy that archive to a linux machine and explore it with `dar`, what would happen?

Thanks!

[1] https://en.wikipedia.org/wiki/AppleSingle_and_AppleDouble_formats
[2] https://en.wikipedia.org/wiki/NTFS#Alternate_data_streams_(ADS)