Yes, you can’t show the UI when the textreview event fires. If you want to make a network request, do it in the plugin code using fetch(url) or change the value of the visible property to false in the showUI method.
This does not require a UI, because the underline range must be returned by the callback function of the textreview event.
This is a requirement not only for Text Review plugins, but also for plugins with parameters. That is, for plugins that work in a restricted environment (queryMode). But I agree with you, it should be described in the documentation.
Is this a plugin for Figma? I can’t find it in the Figma community.
It will be great if you write to the support team for them to respond.