The 4D Pop information page says that the source code is provided for the components, but the source may be difficult to find.
The source code for components from the 4D Pop Collection is included with the installers for 4D v11 SQL.
Check in the SOURCES folder, located inside the component database package (.4dbase) on Mac and in the Component folder (.4dbase) on Windows.
For example, the path on Windows to the source for the 4DPop XLIFF component is:
4DPop XLIFF.4dbase\SOURCES\4DPop XLIFF.4DB.zip