(worked in a earlier old version of 2.8
Short description of error
In earlier betas, it was shown that bone transparency could be set through overlays.
Somewhere in development, this changed in hiding the mesh instead of the bones.
I cannot think of any reason why someone would want to do that
But just in case there is a reason, it might be better to do both.
Go smoothly between making bones more transparent to making the mesh black black
Making bones nearly transparent is handy for modeling with a lot of bones where one would pose a model for a good render composition.
In such a case you want to see surrounding but have some slightly visible bone just to work with, ea moving an arm or so.
without distracting the entire object by bones.
re-opened not fixed.
Transparant bones, to be able to set bone transparancy (in pose mode , overlays the slider there should also have option to make bones transparant ea vanish them (which is much more usefull (for compositional posing) as to setting all other objects to black)