public void close() throws IOException {
			File tempFile = Application.createTempFile("jarBuilder", "treeIDX");
			classTree.trim();
			classTree.saveFile(tempFile);
			try {
				addFile("classModuleTree", tempFile, null);
			}
			catch (CancelledException e) {
				// don't cares
			}
			tempFile.delete();
			jarOut.close();
		}
Puts a directory in the jar for Ghidra Extensions. This may be empty (if
no extensions are installed) but should exist nonetheless.

@throws IOException if there's an error writing to the jar
Ghidra/Features/Base/src/main/java/ghidra/util/GhidraJarBuilder.java