kwallet is actually not a single program but consists of several parts scattered across all of the kde modules.
|| important classes
|| reading/writing kwl files and encryption
|| KWallet::Backend, KWallet::Entry
| UI components
|| provides the client API for kwallet, mostly dbus client stubs
|| the actual kwalletd, currently a module to kded accepting client requests using dbus. This part also has some GUI eg. for authenticating a user.
|| KWalletD, KWalletWizard, KTimeout
|| The application the user uses for managing the wallets and the password entries.