Service Catalog
Structured information about all the services and service offerings of a service provider, relevant for a specific target audience. It is the "menu" of IT.
Impact
The Service Catalog sets expectations. It clarifies what is reliable and supported vs. what is experimental.
Weinto take
The Service Catalog should be a Developer Portal (like Backstage). It shouldn't just list services; it should allow you to instantiate them, view their docs, and check their health. A static PDF catalog is dead; an interactive portal is alive.