Rated 4 out of 5 stars

It seems to be a good add-on and it works as expected, aka. I can see in my Ubuntu 18.04 gnome clock (in the top bar) the events of my Lightning calendar.

BUT, Thunderbird takes 3 more seconds to start (I have removed the add-on and I'm back to normal). I open Thunderbird hundreds of times a day - I can't afford this! Is there a way to speed up what the add-on is doing during start-up or only do it when the lightning calendar is really opened instead of the full Thunderbird start?