Every time I try to download a
.gz file, Chrome appends an extra
.gz at the end of the filename
Is this a known bug? Any workarounds?
Yes, this is a known Chrome bug : Issue 1503: Chrome adds extra duplicate extension.
Reported first in September 05, 2008, it has yet to be fixed (!).
As my understanding goes, Chrome probably mixed up the definitions of several MIME type.
It was indeed a bug, (though I did not realize that it went back to 1503!)
It should be mostly fixed now, although there are still reports of it happening under specific circumstances. However in the latest dev builds (and maybe the latest betas as well) it seems to be working correctly.