@Override
	public ProjectData addProjectView(URL url, boolean visible) throws IOException {
		synchronized (otherViewsMap) {
			if (isClosed) {
				throw new IOException("project is closed");
			}

			if (!GhidraURL.PROTOCOL.equals(url.getProtocol())) {
				throw new IOException("Invalid Ghidra URL specified: " + url);
			}

			ProjectData viewedProjectData = otherViewsMap.get(url);
			if (viewedProjectData == null) {
				viewedProjectData = openProjectView(url);
			}

			if (viewedProjectData != null && visible && visibleViews.add(url)) {
				notifyVisibleViewAdded(url);
			}

			return viewedProjectData;
		}
	}
Get the project URL for this project.
Ghidra/Framework/Project/src/main/java/ghidra/framework/project/DefaultProject.java