This directory hold post-processing scripts for Fusion 360.
It should be linked to '/Users/yona/Autodesk/Fusion 360 CAM/Posts'
They are stored here to protect them from being lost during system upgrades and the like.
Autodesk's post library is here: https://cam.autodesk.com/hsmposts
The manual is here: https://cam.autodesk.com/posts/posts/guides/Post%20Processor%20Training%20Guide.pdf