private Symbol findOriginalExternalSymbol(String name) throws NotFoundException {

		// must examine each external since secondary/original name
		// is not indexed within symbol table
		Symbol candidateSymbol = null;
		SymbolTable symbolTable = program.getSymbolTable();
		ExternalManager externalManager = program.getExternalManager();
		for (Symbol s : symbolTable.getExternalSymbols()) {
			SymbolType type = s.getSymbolType();
			if (type == SymbolType.FUNCTION || type == SymbolType.LABEL) {
				ExternalLocation externalLocation = externalManager.getExternalLocation(s);
				String originalName = externalLocation.getOriginalImportedName();
				if (name.equals(originalName)) {
					if (candidateSymbol != null) {
						return null;
					}
					candidateSymbol = s;
				}
			}
		}
		if (candidateSymbol == null) {
			throw new NotFoundException();
		}
		return candidateSymbol;
	}
Find unique original external symbol with the given name.  
@param name original external symbol name
@return unique external symbol or null if multiple matching external symbols were found
@throws NotFoundException if no original external symbols were found
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/function/ThunkReferenceAddressDialog.java