What is the pink column in the waterfall tests ?

[pqdbr]

Hey guys,

First of all, I would appreciate any tips for optimization in our waterfall below

But not only that, I'd like to understand what goes on in the pink column in the waterfall (it happens before "start render" starts).

Also, any ideas why we get a gap from resource #12 to resource #13 ?

Can parallell connections be increased any further ?

http://www.webpagetest.org/result/120308...1/details/

Thanks in advance !