> It's packaged in Debian and Ubuntu as "doublecmd-qt" and "doublecmd-gtk"

Ah, I found it now. I must have misspelled it, just saw the language files earlier. Yes, this seems to be a valid alternative to Total Commander. It has what I need, including script buttons, very nice. There are still a few bugs, like the buttons are currently all light grey. I will see if I can resolve that. Thanks for this tip.