I'm not sure what you mean.
Spine-Unity doesn't require any specific texture format to work, and in Unity editor, you can choose any encoding that works for your platform.
If you see weird things when you choose a different format, make sure you are aware of this: Premultiply Alpha
This applies to any game engine and any program, not just Spine.
In Unity, if you have specific shader/compression requirements, make sure you set the correct settings and use the correct shader to render the texture. This is in general terms. But from spine, you need to choose the correct settings based on the shader and compression you choose. Normally, if it's specialized, probably turn premultiply alpha off, but that's not always the case.
