Viewing HTML message with Firefox

[José María Mateos]

On Mon, Oct 10, 2022 at 12:27:52PM +0200, Jan Eden via Mutt-users wrote:
>The problem was related to the target dir (/tmp/mutt_attach). Although
>it was accessible by the current user, Firefox was not able to display
>files at file:///tmp/mutt_attach/file.html – while Epiphany was.
>
>Whatever the reason, I changed the script to store HTML files in
>/home/jan/mutt_attach, and Firefox successfully opens
>file:///home/jan/mutt_attach/file.html.

What version of Firefox are you using? I started seeing exactly the same 
problem when I upgraded my Ubuntu installation to 22.04, where Firefox 
is handled by snap, and the filepaths it can access seems to be somewhat 
restricted. I ended up using a solution similar to yours: placing the 
temporary file in a folder within my user folder.

Cheers,

-- 
José María (Chema) Mateos || https://rinzewind.org