You can customize many aspects of Source Insight, such as the color of the screen and the assignments of keystrokes to commands. This collection of options is stored in a configuration file.
Layouts are another type of settings file you can save and load. Layouts contain window arrangements. See: Saving Window Arrangements with Layouts.
The current configuration is loaded and saved automatically, but you can save and load configuration files directly using the Options > Save Configuration and Options > Load Configuration commands. You can also save or load individual parts, such as just key assignments.
By default, all your customizations are saved in a file called config_all.xml, stored in the Source Insight user data directory. This is a global configuration file that applies no matter what project is open.