'7z' can extract .rar archives. Having neither 'rar' nor 'unrar' installed, but '7z' is installed, ark fails to open .rar archive files.
IIRC rar support in 7z is read-only. The problem with ark is that the 7z plugin is read-write, so it expects a read-write backend.
If only 'unrar' is installed, it is also read-only? I can use it to list/extract rar archives, without 'rar' installed.
Yes, the rar plugin falls back to read-only mode if it can't find the 'rar' executable.
I no longer need this, as my distribution decided to disable rar support in 7z, so I have to install both anyway. Unless someone objects, I propose to close this.
Sure, let's close it.