How to allow anonymous access for a REST endpoint?

I am using the JIRA web fragment and trying to create a REST endpoint. I am using a web fragment and its corresponding REST endpoint which is called "MounaBulkSummary". How can I enable "anonymous allowed" for my REST endpoint? You notice my REST endpoint is all the way to the bottom and it doesn't have the option "Anonymous allowed", how can I add it?

Image may be NSFW.
Clik here to view.