https://docs.sencha.com/extjs/7.0.0/modern/Ext.html

Ext.application({
name: 'MyApp',

launch: function () {
Ext.Msg.alert(this.name, 'Ready to go!');
}
});


Ext.Msg.alert(this.name, 'Ready to go!');
should be
Ext.Msg.alert(Ext.manifest.name, 'Ready to go!');

but this does not work on fiddle

MyApp.getApplication().getName()
works, but you use the name 'MyApp' to get the application name 'MyApp', which is pointless.