I'm not sure if I understand you correctly, as machine translation from Chinese is quite ambiguous. Please also always describe what you expect to see and what you got, and also showing the settings you used, instead of just showing an image with a circle. It's hard to guess with which settings the image was taken, and whether you want this as expected result, or whether it's the wrong result.
If you mean that when setting the Spine Editor settings to Linear you see black as a base for the semi-transparent regions where the background is showing: that's indeed a bit distracting, sorry about, it looks like a black background is added to instead of the checkerboard pattern. As version 4.2 will likely not receive any updates in this regard, you could for now add a testing attachment image behind the semi-transparent part where there is no face behind, to see the precise blending also in this area. Note that the blending over the face is showing the correct linear blending behaviour. Setting the Spine Editor color management settings to Gamma space blending will make blending wrong everywhere if you compare it to Linear blending at the runtime in Unity.
