HEAVILY unstable and won't be maintained!
I originally hastily wrote this in a few hours for a short 3D demo/animation I was working circa 2021, and this repository was created only for the sake of archival and 'educational' purposes.
You can place the files in the blender's addon folder (For example, under the folder C:\Program Files\Blender Foundation\Blender 2.93\2.93\scripts\addons\io_scene_obj_adv) and hope your blender will recognize the addon & enable it using the addon menu. Then you can use Export OBJ (advanced) on the export menu to export the (augmented?) .obj file.
This is basically a modification of the existing .obj exporting script, so using it would be almost as exactly the same as the blender's .obj exporter.
The vertex colour will only work with exporting (as that was the only function I needed back in time), And the colour information would be stored after the vertex position values like the following:
(the usual, vertex notation in .obj file)
v x y z
(mesh has vertex colour information)
v x y z r g b a
You probably should use this as a temporary solution at best... I suppose.
Have fun and please don't rely on this too much. Thankyouvermuch - ZIK