I have a PWA app I am testing for offline behavior.
Offline testing of Edge Chromium on an iOS (iPhone) v12.4.1 device. Opening the site offline shows "You're not connected" error page - refreshing the page then shows the cached version until the next GET request again shows the not connected error.
The same offline behavior is observed on the device in Chrome v78.0.3904.84. Keeps showing the "Your're not connected" error instead of loading the pages from cache.
With Safari opening the PWA site offline shows a "Cellular Data is Turned Off" dialog, however when you refresh the page it works as if it were online from thereafter. Still not good, but better. And seems to indicate the issue is in the browser on the client.
Any advice on tools and procedures for testing Chromium on iOS would also be appreciated.