Understanding custom events on modal.js

Understanding custom events on modal.js

Hey guys ! good morning . 

Was just going through modal.js, and saw the following code : 

  1. var e    = $.Event('show.bs.modal', { relatedTarget: _relatedTarget })
i understand its custom events or rather custom namespacing,   but whats with the 2nd parameter ? 

  1. relatedTarget: _relatedTarget  , 
That part is a bit tough to understand . can somebody tell me vaguely whats happening ? I am not expecting a 100% spot on answer .

You can find the same line of code here  , line 53. 


Thank you.

gautam.