PDF file ActivityStarter and Librera

I have a question about ActivityStarter. I have read in http://kio4.com that if I want to open a pdf with Adobe Acrobat Reader from APP Inventor I have to write the following in ActivityStarter (I have tested it and it works):
Action: android.intent.action.VIEW
ActivityClass: com.adobe.reader.AdobeReader
ActivityPackage: com.adobe.reader

But I would like to try with an App called Librera, which is a very configurable ebook reader. The question would be, how should I configure ActivityStarter in this case?

Thank you very much in advance!


TIMAI2 thank you for your response.
I have searched for the info indicated in the link and have obtained the following data:

and with it I have tried this and several ways:
ActivityPackage: com.foobnix.pro.pdf.reader.com.foobnix.pro.pdf.reader.
ActivityClass: com.foobnix.pro.pdf.reader.com.foobnix.ui2

But it doesn't work. Could you help me please!

Thank you very much!!

From what you show in your adb output:

Action: android.intent.action.MAIN

(action may not be required)

ActivityPackage: com.foobnix.pro.pdf.reader
ActivityClass: com.foobnix.pro.pdf.reader.com.foobnix.ui2.MainTabs2