The GEOMETRY_COLOR attribute enables the option to update the color of functions, specified by attribute, by using a Tygron Query Language (TQL) query. It actually does not overwrite the color, so removing the attribute will restore the original color of the model.
As the operation is performed by TQL, the task can be done in the Editor, with the Query Tool. More advanced users can also perform these queries through the API.
For more details about using the Geometry color please consult this documentation:
https://previewsupport.tygron.com/wiki/Geometry_Color