OS: Debian GNU/Linux buster/sid (x86_64)
Even in Firefox it is possible to run "xterm -e mutt" as external mail-client and clicking on a mailto-link, the referenced address will be pasted alright into the mailer-interface.
If you know of a way to do this with the current opera-release for Linux, I'd be thankful for any hints.
The information which appears to have circulated a few years ago, is no longer valid. Something definite from Opera Software would be appreciated, the FAQs and other “official” documentation seems bereft of any mention of external mail-client.
Correct me, PSE, if you can.
There is no such option because chromium (the engine opera now uses) provides no configuration for an email client other than the default one (the one the system uses for mailto: urls).
If you don't want to set Mutt as the default mail client so that Opera can call it, I'd imagine that you'd have to write a script/program and set it as the default mail client. Then, in the script/program, detect if the caller is Opera. If it is, call Mutt with the arguments Opera passed to the script. If the caller is something else, pass the arguments to the mail client that you'd normally want as your default mail client.
As in, make a little mailto broker that handles your Opera case and set it as the default client on the system.