If set, any source changes during the credentials prompts, like the "remember-password" or user name changes, will be automatically stored in the source (written on the disk).
If set, the stored credentials will be returned first. If there are no credentials saved, then the user will be asked. Any credentials reprompt should not have set this flag.
No flag is set.
An #ECredentialsPrompter prompt flags, influencing behaviour of the e_credentials_prompter_prompt().