Question

What does this mean?

allowExeDefinition="MachineToLocalUser"


    <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=99999999999" >
        <section name="MyApp.My.MySettings" type="System.Configuration.ClientSettingsSection, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=99999999999" allowExeDefinition="MachineToLocalUser" requirePermission="false" />
    </sectionGroup>

Answer 1

allowExeDefinition controls the location where the user settings are stored.
For userSettings sections the default is MachineToLocalUser and it means that the section could be stored in Machine.config, exe.config or user.config in the local user profile directory.

Other values for this property are:

• MachineOnly = the ConfigurationSection can be defined only in the
  Machine.config file.
• MachineToApplication = the ConfigurationSection can be defined either
  in the Machine.config file or in the Exe.config file in the client
  application directory. This is the default value.
• MachineToLocalUser = the ConfigurationSection can be defined in the
  Machine.config, in the Exe.config file in the
  client application directory, in the User.config file in the roaming
  user directory, or in the User.config file in the local user
  directory.
• MachineToRoamingUser = the ConfigurationSection can be defined in the
  Machine.config file, in the Exe.config file in the client application
  directory, or in the User.config file in the roaming user directory.