Sorry for my poor englsih.
When I download a ppt presentation (powerpoint) it automaticaly add the .pot extention after the classical .ppt
when I try with a .doc document it automatically add .dot
I haven't done any test with excel files but ...
the problem is that thoose extention or not well recognize by the system (quicklook for exemple).
Safari Version 3.1.1 (5525.20)
This issue is not in open source WebKit, so I'm closing the report as INVALID per our process. This will be continue to be tracked by Apple internally as <rdar://5849742>, thank you for reporting this!