Each row of the product manager interface shows the details of a product you have installed into your vBulletin system.
The image shown above lists two installed products - My Product and Your Product. You can see the description of each product, together with the version number of the currently installed version.
For the majority of users, the product manager will be the interface through which downloaded products are installed, upgraded or removed.
Installed products can be temporarily disabled or fully removed from the system using the corresponding popup menu for each product.
The product manager also acts as the packager for creating new products - this use is described fully in Creating a Product.