Soloing a pattern is a way to view only the rendered pattern as applied to an object without shading effects.
This may help artists place or tune the look of patterns without having to make manual connections for testing. Not that this applies to patterns connected to a BxDF (material) and not a Displacement node.
To solo a pattern, simply select the "Debug" icon or blue stripe on the node. The affected materials will stop rendering other patterns and shading effedcts will be turned off (effectively making it a PxrConstant material).