The "no frontend" bit is quite misleading if you are not aware of the ins and outs of RISC OS filing system stuff.
In the case of any FS, the RISC OS Filer is your frontend when dealing with files and directories. However, typically all FSes also give you a "drive icon" to get to the root of your medium.
Jeffs FS does not do this and therefore relies on the command line to open the root filer window. And also lets you work out for yourself which of your "drives" has which number to get the command line syntax right.