I am currently running Firefox & Thunderbird/Lightning in Ubuntu 16.04 LTS.
I wish to do a clean install of Ubuntu 18.04 LTS with a clean install of Firefox & Thunderbird/Lightning preserving ALL my preferences & data from 16.04.
I do a complete backup (via luckyBackup) of the "Home" folder every time I log on.
Which folder/files should I check for to ensure that I can reload my preferences & data?