Which squashfs file in Ubuntu 22.04 live server image should be used?

I found the squashfs file in Ubuntu 22.04 image pretty much different from previous releases.There is no filesystem.squashfs file under the casper directory after mounting the ISO.Instead, there will be 5 different squashfs files including:

• casper/ubuntu-server-minimal.squashfs
• casper/ubuntu-server-minimal.ubuntu-server.installer.generic-hwe.squashfs
• casper/ubuntu-server-minimal.ubuntu-server.installer.generic.squashfs
• casper/ubuntu-server-minimal.ubuntu-server.installer.squashfs
• casper/ubuntu-server-minimal.ubuntu-server.squashfs

There is a filesystem.manifest but no corresponding filesystem.squashfs.

What's the difference/relationship between them and which one or ones should be used to get the similar contents as filesystem.squashfs of previous releases?