The Libray xpc_addblocks has as first content a Block which does help to clear identify a Signal name later on the Target Screen.
Problem is that when getting a signal directly the path and name are shown on the Target Screen but not clearly defined. Setting these Block and entering a specific name, this name will be displayed clear on the Target Screen.
Take a look on the Screenshot and compare the two signals coming from the Signal Builder with and without this new Block.
TIP: Add to you MATLAB path the path where you saved these files (without MyTestModel.mdl founded in ZIP-File), i.e. path(path, 'c:\my_mfiles');, and you will get through SLBLOCKS.m automatically a new Library (xPC AddOns) shown in the Simulink Library Browser for having a quick access to this new Block. Additional the xPC TargetBox Library will be also enabled on the Simulink Library Browser.
Search on MATLAB central also for NEWXPC, a helper file to create easily new xPC Target based Models. It's a collection of the 'quick access tools' serie.
Enjoy and ThX for your Feedback!