Is your feature request related to a problem?
Yes

Describe the solution or feature you'd like:
I would like to have a function in ClassicCastbars that sends back the cast object as such:

function addon:UnitCastingInfo(unitID)
if not activeTimers[UnitGUID(unitID)] then return end
return activeTimers[UnitGUID(unitID)]
end

I tried to add ClassicCastbars as dependency and add the function to the main lua in your addon just to test, then call from my addon:

local cast = ClassicCastbars.UnitCastingInfo("target")

But its always nil

Any additional context:
I am a complete WoW addon noob just trying to get by in the world

This ^

I won't add an API for ClassicCastbars at this point.

Check out LibClassicCast (maintained by me based on this codebase) or LibClassicCasterino (separate but very similar implementation by the author of NugRunning)