That's a very specific file name! To make sure I'm giving you the right steps, I need a little more information.
: Are you looking to create a specific design feature (like a toolpath or a shape) within a project file that was shared as a .rar?
7-Zip / Feature Requests / #1198 Option to create RAR files?
The file could be related to a few different things, and the process for "creating a feature" depends on which one you mean:
Could you clarify what kind of you are trying to create and what software you are using to open that .rar file?
: Does this involve adding a feature to how you manage or pack .rar files within a specific utility?