Starting in GeneratePress 3.0, the previous Page Builder Container option has been renamed to Content Container option.
Default
The default option means that the Content Padding option in the customizer would apply:
Full Width
The Full Width option set the content area to be 100% of the screen width and allows for full width sections using GenerateBlocks or page builders.
This option also remove the default content padding set in the customizer so GenerateBlocks or page builders can have complete control of the content padding.
Contained
The Contained option simply removes the content padding set in the customizer so GenerateBlocks or page builders can have complete control of the content padding.
Apply the Option to Multiple Pages or Globally
The Layout metabox shown in the first screenshot here allows you to choose the setting per page. You can also create a Layout Element to apply the setting to multiple pages/posts or globally.