sequenceDiagram
    title Subscription Linking - Client-Side Systems Flow
    participant site as Publisher Site
    participant pc as Publisher Center
    participant gcp as GCP

    Note over site: swg.js instantiated 
 with publicationId
    site->>pc: check for valid origin 
 with publicationId
    Note over pc: publicationId maps to 
 SwG OAuth Client Id
    pc->>gcp: OAuth Client ID looked up in 
 linked GCP account
    Note over gcp: Authorized origins determined 
 for OAuth Client Id
    gcp->>site: Authorized origins returned
    Note over site: swg.js successfully initializes
 if instantiated on allowed origin