Do you mean offline hybrid or a native app?
For native this component is in the appstore: https://appstore.home.mendix.com/link/app/114252/
For offline hybrid i don't see a solution and don't expect any solution soon, because of Mendixs stategy to move away from phonegap and towards PWA. Mendix is in the middle of this transition and i think will not invest in phonegap solutions anymore.
But maybe someone else already has a solution, i am curious.
first of all thank you for the answer! I am using offline hybrid.
I hope someone has edit the wdiget from code so the widget can be used offline, or maybe someone has created a widget from zero that uses some pdf viewer library (like pdf.js).
Hope is the last thing you lose.