id's for svg elements

[Bric]

can someone help scope out the task of adding semantically sound unique 
identifiers to the svg elements?

Such that the id bears info on, at least, the staff, (maybe bar), and 
note/chord index (consecutive integer index, for instance)

the "output-svg.scm" script has various routines to build the svg 
elements/tags/attributes, and these are implemented by other scm scripts 
(e.g., "round-filled-box")...

Before I spend hours (days?) trying to figure out the precise subroutine 
chain/tree , perhaps someone can lead me directly to the top-level code 
that feeds lilypond info into these scripts? And whereby one can feed 
staff/movement info, along with note index down to the final svg output?

And is this a realistic goal, I wonder?  I think even just identifying 
CLASS information in the "id=..." attribute might help. Just to set the 
stem "rect" apart from the staff line "rect", for instance, would 
already be an improvement; but, of course, I prefer even more specifics, 
as I described above.

thanks.