Waardering 5 van 5 sterren
Guys, the Monterail Dark and Monterail Full Dark themes STILL work with Thunderbird 68, the reason is they're maintained by somebody else.
They are now listed as Extensions, instead of Themes.
To get them, (1) browse the Thunderbird Extensions, (2) search for Monterail Dark or Monterail Full Dark, (3) install those extensions, (3) make sure they are, for now, deactivated, (4) in Thunderbird, choose to have the Default theme, (5) and finally, back in Extensions, activate either Monterail Dark, or Monterail Full Dark.
Enjoy, and thanks a lot to the kind maintainer of Dark and Full Dark :)