Comment 11 for bug 756247

mere user writes:

> so at some point ("original value" above) it did get the right idea,
> but then it reverted back to the three values ("application"
> "x-unknown" "application/x-gzip"). adding external types to
> deleteable types is not necessarily a bad idea if it works. but if it
> cannot work then, of course...

The moral is to not depend on external-types-alist and set the variables
fully yourself.

I am not sure it is a good idea to insert the external-types either. For
instance, I have an external viewer defined for text/html, even though I
view it internally most of the time. It shouldn't be considered a
deleteable type just because there is an external viewer defined for it.
(This is not actually a problem with the defaults because Rob had excluded
all text types in the deletable-type-exceptions. But the principle is still
the same.)

Cheers,
Uday