The only thing i see possibly having to do with it is that between the end of the header and the start of the text (not the content entity) there are 3 line breaks.
Where HTTP/1.0 would supply the text right away, HTTP/1.1 adds a chunk length, in hex, spanning one line.
In groups.yahoo.com i get:
header
122a
<HTML>
with HTTP/1.1, and with HTTP/1.0 i get
header
<HTML>
As you can see, there really is only one line break. My theory is Mozilla includes the line break succeeding 122a, the chunk length, in the source.
But it's just a theory.
-nuffin
zz zZ Z Z #!perl