All the shared materials of this object.
This is an array of all materials used by the renderer. Unity supports multiple objects
using a single material; in this case sharedMaterials contains all the materials used for this.
sharedMaterial and material properties return the first used material if
there is more than one.
Modifying any material in sharedMaterials will change the appearance of all objects
using this material, and change material settings that are stored in the project too.
It is not recommended to modify materials returned by sharedMaterials.
If you want to modify the material of a renderer use material instead.
Note that like all arrays returned by Unity, this returns a copy of materials
array. If you want to change some materials in it, get the value, change an entry and
set materials back.
Additional resources: material, sharedMaterial properties.