private void mapResultsToOriginalLibs() {
		SymbolTable originalSymbolManager = originalPgm.getSymbolTable();
		String[] originalNames = originalExtMgr.getExternalLibraryNames();
		for (String originalName : originalNames) {
			Symbol librarySymbol = originalSymbolManager.getLibrarySymbol(originalName);
			long originalID = librarySymbol.getID();
			long resultID = getResultIDFromOriginalID(originalID);
			if (resultID != -1) {
				resultToOriginalMap.put(resultID, originalID);
			}
		}
	}
Populate the reverse map for the Library symbols in the Original program.
Ghidra/Features/Base/src/main/java/ghidra/app/merge/listing/ExternalProgramMerger.java