private void resolveExternalSymbols() throws CancelledException {
			unresolvedExternalFunctionIds = getUnresolvedExternalFunctionIds();
			externalSymbolCount = unresolvedExternalFunctionIds.size();

			if (unresolvedExternalFunctionIds.isEmpty()) {
				return;
			}

			extLibs = getLibsToSearch();

			if (!extLibs.isEmpty()) {
				try (Transaction tx = program.openTransaction("Resolve External Symbols")) {
					for (ExtLibInfo extLib : extLibs) {
						monitor.checkCancelled();
						resolveSymbolsToLibrary(extLib);
					}
				}
			}

		}
Represents a program that needs its external symbols to be fixed.
Ghidra/Features/Base/src/main/java/ghidra/program/util/ExternalSymbolResolver.java