Translation location

I'm upgrading safely by reinstalling CP 2.x on a new subdir.
With new core files and newest translations etc.
As from 1.0 to 2.0 was turning into a terrible thing...

For now a relative simple question, I'm translating CP language files online and
searching for "save_progress_and_exit" element > textual "Save progress & Exit".
Can you help me to find out where this is listed in the strings?
In the Core CP files or Themes?