Vertex Colors window
Use the Vertex Colors window to apply vertex colors onto an entire Mesh or only a portion.
To open this window, go to Main Menu > Tools > ProBuilder > Editors > Open Vertex Color Editor.
(A) Click the Reset button to return all the colors on the Color Palette to their default values.
(B) You can import your own swatch library and use its colors instead of the default Unity colors. To do this, set a reference to the swatch library file.
(C) Click the Apply button to set the associated color on the selected object(s) or element(s).
(D) Use the standard Unity Color Picker to pick a custom color for the palette.
(E) Use the eyedropper to match a custom color for the palette.