For release R12, the Integration Repository comes bundled with your Oracle E-Business Suite instance. In 12.0.X releases, Integration Repository is available as a Responsibility. But in 12.1.1 release, it is available under Integrated SOA gateway responsibility.
For R11 you can also look into the regular manuals
Hope this helps
In My Oracle Support try these Notes:
For Release 12, please refer to 11.5.10 Oracle Manufacturing APIs and Open Interfaces Manual.
The following note also outlines changes to the Interface tables - upon moving to release 12:
Note: 437587.1 Release 12 Oracle Purchasing API and Open Interface Changes.
The release 11.5.10 Oracle Manufacturing APIs and Open Interfaces Manual can be found using the
following note - it is the fourth entry under the 11.5 section:
Note 67108.1 - Procurement (Purchasing) Product Documentation
There was also an addendum to the 11.5.10 Oracle Manufacturing APIs and Open Interfaces Manual which is
located in the following note:
Note 359295.1 - Oracle® Purchasing Release 11i10 Open Interfaces and APIs