Add allowed bundle types as argument to hgweb unbundle capability. Arguments to capabilities were added before the 0.9.1 release, so there are no compatibility issues. Mercurial 0.9 didn't support http push. Using HG10GZ, HG10BZ and HG10UN has the advantage that new bundle types can be added later and the client doesn't have to try sending them first and reacting on errors sent by the server.

200 Script output follows
content-type: text/plain
content-length: 157
content-disposition: filename=sometext.txt

This is just some random text
that will go inside the file and take a few lines.
It is very boring to read, but computers don't
care about things like that.
host - - [date] "GET /?f=f165dc289438;file=sometext.txt;style=raw HTTP/1.1" 200 -