The RTE Location lets you add/ create custom plugins to extend the functionality of your JSON Rich Text Editor as per your needs.
You can use third-party applications to interact with your JSON Rich Text Editor content.
Let's see how to add the RTE location to your app:
Via the Developer Hub Console:
To add the RTE location to your app via the Developer Hub console, login to your Contentstack Account and follow the steps given below:

Properties that can be specified for this UI location:
You can configure any UI location as mandatory using the Required toggle. If the toggle is enabled, the location becomes mandatory and cannot be disabled. Whereas, if the toggle is disabled, the UI location is available to use but not mandatory.
Additional Resource: Refer to the Marketplace App Manifest documentation for comprehensive details.
You will see the details of the configured UI location on the UI Locations tab in the App Configuration screen after installing the app.
You can enable or disable the non-required UI locations.
Navigate to the stack. You will see the installed app in the JSON RTE field in the entries page.
You can create new RTE locations by writing your custom code, or you can use the prebuilt boilerplate and modify the given code to suit your requirements.