Toning meshes without textures?

[DanishXDCPA (DanishThe)]

Hello,
I found this jet model in the Marketplace which I believe originates from the game Jailbreak.

Asset:

Creator Hub - Store

I noticed that it has no textures, yet has those darker spots. How does one achieve this?

[awry_y (Harper_Clark)]

This is done by using vertex painting.

Introduction to Vertex Paint Mode (blender 2.8)