There should be an alternative method to restart a loaded savegame with the settings used for that savegame.
There was an effort to make 'restart' attempt to re-create the same world starting from the generating process, and making most of the world gen settings saved on the savegame played a part for that to happen.

That effort seems to have gone forgotten with this feature now in master.

Originally posted by @SamuXarick in #7328 (comment)

I used the lost feature to re-test AIs, to spot differences in their doings, to debug possible world generation issues when working on the code, and sometimes just to recreate a multiplayer game from fresh. It was really useful.