sorry for the laaaaate reply: I am a student (not studying IT though!) and this addon was the result of my very own needs and I published as a challenge to myself.
Glad you appreciate it! I don't promise I will code what you're asking, time is quite absent and I am always busy: can you please provide an example of what could be useful with "saving a group of tabs" as you wish?
You could do it tab per tab: do you feel like a waste of time?
Or do you prefer that all the tabs to be saved in a unique txt file? (You could do that easily with some bash).
Waiting for a reply from you, thanks for your review!!!