How to add an entry to the sprint options (spin button), in the backlog

Hello,

We would like to add an entry to the sprint options spin button, in the backlog page. How can we do it? We’ve searched through all “UI Locations” pages we could find in google and came up with nothing.

Is it at all possible?

Is there somewhere that details all possible UI Locations within JIRA? The information on this seems to be scattered all over the Atlassian developer docs.