SquashFS can be easily mounted, so it's often more convenient than usual archives for backups and other purposes.
No root required (but there is an option to use root).

When using zstd compression, you can choose compression level.

Supported languages: Dutch, English, Russian

Installation: place the file in ~/.local/share/kio/servicemenus

See also SquashFS mounter / unmounter (no root required, too): https://pling.com/p/1410382