Not sure why it's called a burr nor why XYZ are used for, but the thing I know is that this is a very nice metal puzzle designed and made by R.D Rose some time ago.
The colors are nice and the shape as well. You cannot go wrong with a R.D Rose puzzle as I think they belong to the most original metal puzzles.
The goal is to disassemble it, but if you have the opportunity to play with it, I advise that it's shown to you disassembled. Indeed, separating the pieces is very easy and can be done even by a child. Reassembling the pieces is the real challenge!
The pieces are identical and there is no clear hints how the pieces could go together and it can even seem that they cannot be put together...
Obviously a co-motion move will have to be done at some point, this is not a spoiler!
I think this is a pleasant puzzle to play with either by burr lovers who can think they will have to solve a burr or by non-burr lovers who will actually play with not a burr (yes, this is not a burr at all despite the name!!) :-)