Hello,
there is a bug in the GPL version concerning

1. the licence message shown by `npm start`.
It shows
Code:
 i [ext]: ext-webpack-plugin v7.0.0, Ext JS v7.0.0 Commercial Edition, Sencha Cmd v7.0.0.40, webpack v4.39.3n/a
instead of showing GPL Edition (as ext-gen does)

2. The generated app shows a watermark telling "Ext JS Trial"

See also the question on SO

What is the official method to remove that watermark ?