Feature summary (what you would like to be able to do and where):

As a tool developer I would like to be able to use the action API to retrieve the list of domains allow-listed for uploads by url as JSON.

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):

I don't want maintain local copies of MediaWiki:Copyupload-allowed-domains in my tool(s) nor proxy it and in the best of worlds not even parse the raw contents.

Benefits (why should this be implemented?):

To reduce maintenance and work for developers