Kconfig files describe build-time configuration options (called symbols in Kconfig-speak), how they are grouped into menus and sub-menus, and dependencies between them that determine what configurations are valid.
Kconfig files appear throughout the directory tree.
subsys/pm/Kconfig defines power-related options.
All Kconfig options can be searched using the search functionality. The search functionality supports searching using regular expressions. See Regex tips and tricks for more information. All the Kconfig options that match a particular regular expression is displayed along with the information on the matched Kconfig options. The search results can be navigated page by page if the number of matches exceeds a page.