Roadmap: Define metrics populated on bars

I created a custom roadmap so that release details (date, capacity, feature original estimate, work done and work remaining over capacity) populate on top of bars in respective swimlanes. Seems few metrics appear which define values to a given release (i.e. release name, release date) but other details carry over only as numerical values or days, which doesn't provide the information I want to convey (i.e 20d, 13d, 0, 0). I want to define what "20d, 13d, 0, 0" means on bars in a roadmap view. 

Included attachment for reference

Thanks for sharing this idea. We would like to better understand your use case. Can you share more about the type of roadmap you are creating?