Chisel

The Matcap panel picks the lit-sphere image every shape is shaded with, and a tint over the whole scene.

the Matcap panel

Settings

SettingDefaultWhat it does
Matcap (the preview)the first matcap in the listClick it to open the matcap grid and pick one. The list is Blender’s own matcaps.
SpecularonShown only when the matcap has a separate specular layer. On adds the matcap’s highlights; off keeps just the diffuse layer.
Colour swatchwhiteA tint multiplied over the matcap for every shape. White leaves the matcap untouched.
Reset (the arrow button)Sets the tint back to white.

Each shape’s own colour comes from its Chisel material and is multiplied into the matcap under this tint.

Matcaps added in Preferences ▸ Lights ▸ MatCaps (.exr or .png) appear in the grid too. The file stores the matcap by name, so it keeps its matcap on another machine; a name this machine lacks falls back to the first matcap.