Container Disk 2 Structure

Greetings from Australia

I recently purchased a 2023 Mac Mini M2 with 16 MB memory and 1 TB SSD running Ventura. This took over from a late 2012 iMac with 24 GB memory and a 3 TB Fusion drive, running Catalina.

I decided to install Parallels on the iMac to run Windows 11, and use the large fusion drive as a combination of an archive and possibly a server. Once I set up the Mac Mini as I wanted, purged a lot of stuff from the iMac and set it up from scratch with a full reinstall of Catalina (It's too slow to run Ventura via Opencore Legacy Patcher).

I browsed the iMac's structure after the rejig, and found that I had a new volume under Container Disk 2 named "disk2s4". I dug deeper and found that /dev/disk2 is labeled "Synthesized". I don't believe that i have mysteriously acquired another 3 TB of disk space but I can't find any information about disk2s4. Does anyone have any info about this? My questions are...

• What is disk2s4?
• Can I delete it?
• Can I hide it? If so how? (shift-command-. doesn't work.

I have included a couple of screen-dumps that I hope clarifies it.

I hope someone can shed some light onto disk2s4

Thanks