Engine analysis questions - Lc0 and custom positions

1. I noticed yesterday that I can easily install Leela chess zero software with Linux but is there a GUI for it ?

2. A friend told me that Fritz and ScidvsPC refuse to load a FEN like this :
   https://lichess.org/editor/rnbqkbnr/pppppppp/8/8/PPPPPPPP/RNBQKBNR/pppppppp/qqqqqqqq_w_kq_-_0_1
   With PyChess I can actually load such a position and let an engine analyze. With Pychess I can even load a position
   with more than 2 kings (vchess dot club/#/variants has a variant with 4 kings)
   Why the difference ?

There is an interface for Lc0, it's called Nibbler: https://github.com/fohristiwhirl/nibbler - very nice project, sleek and easy-to-use/install.

As for why Scid fails to load the above FEN? Possibly because Scid/Fritz/Arena etc allows only Standard chess, and therefore having more than 32 pieces on the board breaks the system, even more so when more kings are introduced :)

I just tried with Scid vs PC, and returned an error: "... is not a valid FEN"!

@zzhangb4
Great, thank you !

I like GUIs like Nibbler or Banksia GUI which are designed for Leela. Such GUIs can use the sort of information Leela provides that other engines don’t.

Edit: I see that Nibbler was already mentioned in this thread.