I've tested on stretch with Firefox 52.2.0esr-1~deb9u1 Epiphany 3.22.7-1 Thunderbird 1:45.8.0-3 (using xul-ext-tbdialout 1.7.2-1)
and I'm pleased to see it working, except for one unrelated tbdialout bug. To test, I created /home/daniel/bin/sipdialer-test: #!/bin/bash echo $1 >> /tmp/sipdialer.log and ~/.local/share/applications/sipdialer.desktop [Desktop Entry] Name=sipdialer GenericName=Click to dial Comment=Click to dial Type=Application NoDisplay=true TryExec=/home/daniel/bin/sipdialer-test Exec=/home/daniel/bin/sipdialer-test %u Terminal=false Categories=System Icon=/usr/share/icons/hicolor/48x48/apps/vlc.png MimeType=x-scheme-handler/tel; and also edited .local/share/applications/mimeapps.list [Added Associations] ... x-scheme-handler/tel=sipdialer.desktop ... Then I ran "update-menus" and I was able to click a "tel" link in Firefox and it launched ~/bin/sipdialer-test with the phone number as an argument. GNOME Evolution in stretch also supports the same handler now[1] and I tested that too and it passes a similar URL to the handler. That means the same handler script (maybe sipdialer from reSIProcate or something else) can handle the "tel:" URI (click-to-dial) from Firefox, Thunderbird and Evolution. One problem I noticed with tbdialout: it strips the leading "+" from the phone number. It is necessary to add it back in the plugin preferences, under "Replace leading + with:", maybe it should be there by default as it is non-intuitive what will happen when that field is blank. Regards, Daniel 1. https://bugzilla.gnome.org/show_bug.cgi?id=729084
