From Fedora Project Wiki

Product image

How to Create an Anaconda Product Image

Anaconda supports several ways to load new code at runtime. Passing inst.updates=<url> is one way to do this and is documented on the updates page. Another is to include a product.img in the install tree, inside the /images/ directory. It will be applied at runtime and can overwrite any file on the system, just like the updates.img.

One use for a product.img is to add a new installclass to Anaconda. A product image for a new installclass can be created from a directory of files like this:

mkdir -p product/run/install/product/pyanaconda/installclasses/
vim product/run/install/product/pyanaconda/installclasses/

Create new installclass, see Anaconda for examples. Now you can create the product.img:

cd product/
find . | cpio -c -o | pigz -9cv > ../product.img

Now you can include product.img in the tree, inside /images/.

Alternatively, you can now use lorax to create product.img as part of the boot.iso creation process. This is supported by lorax-21.27-1 and is documented here in the Lorax source tree.