I assume that you talk about this component?
Latest components are available on SourceForge, see McuOnEclipse Components: 26-Dec-2017 Release | MCU on Eclipse
The sources for the components are hosted on GitHub - ErichStyger/McuOnEclipse_PEx: McuOnEclipse Processor Expert Source Files and Components
If you are interested where the files are installed on your machine, see CDE Hacking: Where is my stuff? A dissection… | MCU on Eclipse
I hope this helps,
Erich