To make it clear
By default you get
Package: io.kodular.email.projectname
Class: io.kodular.email.projectname.Screen2
If you change package name in Kodular e.g. com.example.projectname you get
Package: com.example.projectname
Class: io.kodular.email.projectname.Screen2
Real package name e.g. com.example.projectname you get, see more at App Inventor Tutorials and Examples: Package name | Pura Vida Apps
Package: com.example.projectname
Class: com.example.projectname.Screen2