We have communication between the uxp panel and WebView. But is there communication API between two panels? Because sometimes we want to split plugin in the separate parts (separate windows) but still having a way to communicate would be nice.
A single plugin may have as many panels as you want. If I understand your request correctly, there’s no need for separate plugins to get separate panels
I guess this could be an answer https://developer.adobe.com/indesign/uxp/plugins/tutorials/inter-plugin-comm/