Displaying PDF in PyQt5 QWebEngineView and getting content of non-url links

Question

I use PyQt5.QtWebEngineWidgets to display a pdf. In this pdf I added links over certain words with PyMuPDF. The links are created with this code:

def create_pdf_with_links():
    doc = fitz.open("test.pdf")
    for count, page in enumerate(doc):
        text_instances = page.search_for("Kontrollstelle")
        for instance in text_instances:
            d = {'kind': 2, 'xref': 0, 'from': instance, 'uri': 'data:Hallo Welt', 'id': ''}
            page.insert_link(d)

    doc.save("test.pdf")

Now I want to get the data saved inside the links, when I click on them. Therefore I modified QWebEnginePage and the link scheme based on another question of mine. Unfortunately, I don't get any response, when clicking on the link. When I add a typical url as link content, the corresponding page is loaded. The code for displaying the pdf and handling the link looks like this:

class MyWebEnginePage(QWebEnginePage):
    dataLinkClicked = pyqtSignal(str)

    def acceptNavigationRequest(self, url,  _type, isMainFrame):
        if (_type == QWebEnginePage.NavigationTypeLinkClicked and
            url.scheme() == 'data'):
            # send only the url path
            self.dataLinkClicked.emit(url.path())
            return False
        return super().acceptNavigationRequest(url,  _type, isMainFrame)

class App(QMainWindow):
    def __init__(self):
        super(App, self).__init__()
        self.pdf_path = os.path.abspath("test.pdf")
        webView = QWebEngineView()
        page = MyWebEnginePage(self)
        # connect to the signal
        page.dataLinkClicked.connect(self.handleDataLink)
        webView.setPage(page)
        # use a data-url
        webView.settings().setAttribute(QWebEngineSettings.PluginsEnabled, True)
        webView.settings().setAttribute(QWebEngineSettings.PdfViewerEnabled, True)
        webView.setUrl(QUrl.fromLocalFile(self.pdf_path))
        self.setCentralWidget(webView)

    def handleDataLink(self, text):
        print(text) # should print the link: "Hallo Welt"


if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = App()
    window.setGeometry(800, 100, 1000, 800)
    window.show()
    sys.exit(app.exec_())

How do I get the data from the link?