On Wed, 07 Feb 2018 04:04:56 +0800, Dan Jacobson wrote: > # su - nobody -c 'HOME=/tmp/ff emacs'& #Total clean environment. > M-x w3m
> At this point a connection to "about:" is caught by TRAMP. At that time emacs-w3m is about to access the url "about:", and runs (file-exist-p "about:") at first in order to check whether "about:" is a local file. But IIUC, it should not trigger TRAMP; only a thing like "/about:" will trigger TRAMP. I can reproduce the same error with (file-exist-p "/about:") and a similar error with (w3m "/about:"), though such ones should not happen. Funny.