https://extensions.blender.org/add-ons/import-export-skin-weights/
An simple add-on for Blender Exporting and Importing skin weights from mesh to JSON using Position or UV mapping method.
Use to export vertex group, UV position and influences of all vertex of selected mesh to JSON file, then can be reimported with any mesh with same hierachy skeleton. (works best with meshes with same topology, or same UV)
Position mode: Map by closet vertex position
UV mode: Map using vertex UV coordinate
Workflow:
Select mesh > Export Button > Save in folder
Select mesh > Choose Mapping method > Import Button > Find the JSON file
Detail processing here: https://www.youtube.com/watch?v=a4UmL9ietJU