Mailto (xdg-open) still not working on Linux

xdg-mime query default x-scheme-handler/mailto returns:
thunderbird.desktop

However:

xdg-email [email protected] returns:
/usr/bin/xdg-email: line 599: thunderbird.desktop: command not found

But that’s incorrect. thunderbird.desktop does exist in /usr/share/applications and here’s what it says:

[Desktop Entry]
Categories=Network;Email;GTK;
Encoding=UTF-8
Name=Thunderbird
GenericName=Mail/News Client
Comment=Mail/News Client
TryExec=thunderbird
Exec=thunderbird %u
Icon=thunderbird
Terminal=false
Type=Application
StartupNotify=true
MimeType=x-scheme-handler/mailto;

Footnote: Not that it matters, but I’m also working on an OpenSuse (stable 15.2) system with the exact same problem.