Extension debugger is clearing the scripts map on Page.frameStartedLoading event, and Webkit debugger is clearing the scripts on Debugger.globalObjectCleared. The former is fired during hot restart or page reload, and the latter is not.

Extension debugger

Webkit debugger

https://github.com/google/webkit_inspection_protocol.dart/blob/da43164be2387157671c88be9d3acd26a1806b47/lib/src/debugger.dart#L162

This causes differences in behavior in flutter for web:

• Using debug extension with Web server device: breakpoints are not resolved correctly after a reload/restart
• Using webkit debugger with Chrome device: breakpoints are working normally.

See: flutter/flutter#101224 (comment)