What is Extension Management for Business Central?

What are Business Central Extensions?
Extensions for Business Central allows you to make customizations or add extra functionality to Dynamics 365 Business Central without making any changes to the base code itself.

On the Extension Management page, you can see the apps that are currently installed, and you can open the Extension Marketplace page that shows the Business Central apps that are currently available in AppSource. If you choose the 'more apps' link, you're taken to AppSource.microsoft.com. For each extension you can review the installation name, description, version, App ID, and perform installation/uninstallation routines.

Install and Uninstall Extensions (Apps) in Business Central