So i have a question, i just hit inspect element on the Material Design Guide because i wanted to know the specs of the Dividers (I know those are very well explained in the guide) but i wanted to make a double check and suddenly in Family Fonts i read "roboto draft" so i google it and people said that it was Roboto2 before it was Renamed as "Roboto" as we know it.... And so my mind wonder, Why do they keep Roboto Draft on their Family Fonts library? is it lighter? is it a browser version thing? or there is a more technical explanation for that? ...
And the reason im asking this with such emphasis is because in my office we are developing a WebApp with all the Material Design Specs and well....im a very curious designer.
UPDATE: Robto Draft Regular Weight: 22kb | Roboto Regular weight: 145 kb
So assuming that this weight difference is constant across the whole family then thats the reason.