For iOS:
    
      Open the iOS folder of your Flutter app in Xcode
      Select a Simulator as the target, and click Run button
      In Xcode, select
Xcode > Open Developer Tools > Accessibility Inspector

      In the Accessibility Inspector,
select Inspection > Enable Point to Inspect,
and then select the various user interface elements in running
Flutter app to inspect their accessibility attributes
      In the Accessibility Inspector,
select Audit in the toolbar, and then
select Run Audit to get a report of potential issues

For web:
    
      Open Chrome DevTools (or similar tools in other browsers)
      Inspect the HTML tree containing the ARIA attributes generated by Flutter.
      In Chrome, the “Elements” tab has a “Accessibility” sub-tab 
that can be used to inspect the data exported to semantics tree

Large fonts