Before Embedded Wizard version 13 this attribute was used to specifies a name prefix for the generated code files.

The attribute OutputPrefix was intended to support customer specific build processes being dependent on predetermined file naming convention. In particular, it allowed the customer to specify a prefix the Code Generator puts in front of every generated file name.

The value of this attribute was considered as a suggestion for the Code Generator. If the selected Platform Package was not able to evaluate this attribute, the prefix was ignored.

With the version 13 the attribute OutputPrefix has been declared as deprecated. Accordingly, this attribute is not listed anymore in the Inspector window when you have selected a profile member.