Good catch.
It's the 2005 one.
According to the following definition in the SQLServerDQE /DynamicQueryEngine.cd
private static SqlServerCompatibilityLevel _defaultCompatibilityLevel = SqlServerCompatibilityLevel.SqlServer2005;
Also in the generated DataAccessAdapter.cs it's mentioned that the default is 2005
private Nullable<SqlServerCompatibilityLevel> _compatibilityLevel = null;
/// <summary>The per-instance compatibility level used by this DQE instance. Default is the one set globally, which is by default SqlServer2005 (for 2005+).
/// Compatibility level influences the query generated for paging, sequence name (@@IDENTITY/SCOPE_IDENTITY()), and usage of newsequenceid() in inserts.
/// It also influences the ado.net provider to use. This way you can switch between SqlServer server client 'SqlClient' and SqlServer CE Desktop.</summary>
public Nullable<SqlServerCompatibilityLevel> CompatibilityLevel
{
get { return _compatibilityLevel; }
set { _compatibilityLevel = value; }
}