So I did a reinstall and forgot to run MozBackup on my old OS before I wiped it. I did however get a drive backup and copy of my C:Users folder.
Turns out with Mozilla (browsers and email clients) you can copy the contents of the profile folder, into the new one. The folder name should remain the same on the new PC, so copy the contents of the old profile into the new one.
C:Users$Username$AppDataRoamingMoonchild ProductionsPale MoonProfiles$string$.default
This will restore all your history, logged in sessions and likely saved password, if you do the saved password thing.
I found it amusing that a new machine with the folder contents copied over, registered as the same machine. Interesting vector if you are an exploiter or hand lots of system deployments with data migration.
Remember, what is nefarious for one person, can be used to help someone else out.
Replace the Pale Moon path with a relevant Firefox install directory. It will also live in the Roaming portion of your profile AppData folders. Pale Moon is a forked browser based off Firefox.