The Extra Modules module Journal > Product Extras > Extra Modules. is a special position container for the product page. It offers maximum control and flexibility for any layout modules to be added inside the product page details area.
This is not a typical module but rather acts as a "module container" for any other layout module. It leverages the Page Builder so you can create one or more such "module containers" and assign them to the product page in the pre-defined positions
ANY layout module (Blocks, Sliders, Banners, Forms, Products, etc.) can be loaded in Extra Modules containers so there is unlimited creative freedom in decorating the product page with any other module.
Typical use for the Extra Modules is for social share plugins created with the Blocks module, Products or Mini Products modules, etc.
You can add Extra Modules in between product details (stats, options, add to cart) by indicating custom sort orders for each section in the Product Page Style Journal > Styles > Product Page > Product Details > Blocks/Tabs > Sort Order. Likewise, any other section from the product details can be custom sorted and thus unlimited layout combinations are possible.
See Product Assignment for more info on how this concept works. You can assign modules to all products, individual products or a custom set of products matching a certain criteria or rules.