When using the DeveloperProfileLoader, the plugin will generate a name for the Keychain based on this code:

String keyChain = "jenkins-"+build.getProject().getFullName().replace('/', '-');

https://github.com/jenkinsci/xcode-plugin/blob/2f8f70/src/main/java/au/com/rayh/DeveloperProfileLoader.java#L52

This is a request to have that name exported as an environment variable, to avoid having to hardcode the same logic in other parts of the build script.

Currently, to access the generated keychain in a shell script, it has to be written like this:

security show-keychain-info "jenkins-${JOB_NAME/\//-}"

This request is so the same shell could be done like this:

security show-keychain-info "${KEYCHAIN_NAME}"