The 250 last completed commands. You have the usual controls to browse the list.
You can hit the redo button to open a dialog in which you can re-start an (edited version of) this command and of course you can (re-)rank the images and use all other controls of the image displays.
When you run several commands to find the best and continue with that one, history can be handy to keep track of these. (HINT: So can ranking these images with 1 and then use the images tab, locating the last images with ranking 1)
Another use case: When you have hit "To History" too fast in the Ready tab, you still can use the command by going to the newest (last) command in History.
Browsing history for inspiration is a possibility too, although the images tab might be a lot better suitable.
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