Buried in the properties of each component that is placed in any of the Altium Designer editors is a property called the Unique Id. This randomly generated 8 alpha character codes provided to each component to assist Altium Designer in its netlist management.
The Unique Id plays a major role in Altium Designer's ability to maintain continuity between the schematic and PCB netlists. Yet, it tends to do its job so well that most users don't even know it's there!
However, A little knowledge about these Unique Id goes a long way in assisting users in establishing connectivity in imported designs, connecting schematic and PCB snippets, and even reconciling potential issues to duplicating schematic files in the same project.