I can create a controller for created contentType, ex: api::restaurant.restaurant.
api::restaurant.restaurant
But for built-in plugins, ex: plugin::users-permissions.user, I don’t know where to put the controller.
plugin::users-permissions.user
Hello @Unviray, this link could be helpful CLICK ME
You are correct that this is different than creating a controller for a regular content-type that you’ve created. In the case of extending a pre-existing plugin, you would use the extensions dir for it.
extensions
See Plugins extension - Strapi Developer Docs.