[emacs-w3m:13850] emacs-w3m and youtu.be [FOLLOW-UP]

There is a solution #3 which really should be solution 1.5, which is to
add an entry to variable w3m-user-agent-site-specific-alist. Something
like this (untested):

 ("^https?://youtu.be/" . "Linux Firefox")


=2D-
hkp://keys.gnupg.net
CA45 09B5 5351 7C11 A9D1  7286 0036 9E45 1595 8BC0