If you have a puredata.info account, you should be able to update it.
but I wonder if there's a way for Pd to allow us to go there. There certainly is, but seems it won't be too simple…+1 on this. There should be a simple way to open the current externals folder, like how many macOS applications have a option to “Show in Finder” for various content. This could be a button in the deken panel or a menu option in Help, etc.