xdg-email tries to execute thunderbird.desktop

kreadconfig5 --file emaildefaults --group PROFILE_Standard --key EmailClient returns thunderbird.desktop. xdg-email uses that verbatim to execute the mail client, which fails as .desktop files themselves are not executable.

            if echo "$client" | grep -Eq 'thunderbird|icedove'; then
                run_thunderbird "$client" "$1"
            fi

run_thunderbird()
{
    THUNDERBIRD="$1"
...
    "$THUNDERBIRD" -compose "$NEWMAILTO"
}

Possible fixes:

• hard-code executing thunderbird instead of passing it via $1 - this would break icedove, but this is no longer supported by/required for Debian.
• Use ${THUNDERBIRD%.desktop} to strip the suffix - would breaks if I have a custom thunderbird.desktop with Exec=/some/thing/completely/different
• Parse the .desktop to get Exec= from it
• Use xdg-open to execute the .desktop file? open_generic() already does that.