When you create a custom module in HubSpot, you can set it to be a global or local module. Once this is set, it cannot currently be changed in the Design Tools GUI but you can update it through the CLI.
In the CLI, your module's meta.json file will look something like this:
Update the global value to false to convert it to a local module.
⚠️ However, there's a bug that's been around for a few years in which you'll now no longer be able to see the fields for that module (🙀)
To fix this, go into your fields.json file, and if you look at some of the fields, you'll find that they're set to "locked" : true. Change this to "locked" : false and they'll be editable again.
(I'm mainly writing this post because I come across this every once in a while. I always remember "there was some quirk about switching from global to local" but can never remember what it is - this is for you, future Stephanie).
