Returns `string` - User friendly name of the password manager selected on Linux.
This function will return one of the following values:
*`basic_text` - When the desktop environment is not recognised or if the following
command line flag is provided `--password-store="basic"`.
*`gnome_libsecret` - When the desktop environment is `X-Cinnamon`, `Deepin`, `GNOME`, `Pantheon`, `XFCE`, `UKUI`, `unity` or if the following command line flag is provided `--password-store="gnome-libsecret"`.
*`kwallet` - When the desktop session is `kde4` or if the following command line flag
is provided `--password-store="kwallet"`.
*`kwallet5` - When the desktop session is `kde5` or if the following command line flag
is provided `--password-store="kwallet5"`.
*`kwallet6` - When the desktop session is `kde6`.
*`unknown` - When the function is called before app has emitted the `ready` event.