diff --git a/apps/editor/src/app/App.tsx b/apps/editor/src/app/App.tsx
index cb69939..f9dc9e3 100644
--- a/apps/editor/src/app/App.tsx
+++ b/apps/editor/src/app/App.tsx
@@ -618,7 +618,7 @@ function AppInner() {
       try {
         const alignmentDocs = await api.listAlignmentFrameworks({ tenantId, participantId: sourceId })
         return alignmentDocs.flatMap((doc) => {
-          const participants = doc.alignmentParticipants ?? []
+          const participants = doc.extensions?.['ext:opencase']?.alignmentParticipants ?? []
           const other = participants.find((p) => p.identifier !== sourceId)
           // No distinct "other" participant means this is a self (intra-framework) alignment doc.
           const targetIdentifier = other?.identifier ?? (participants.some((p) => p.identifier === sourceId) ? sourceId : undefined)
@@ -646,7 +646,7 @@ function AppInner() {
         // for a self-alignment (targetId === activeFrameworkId) matching "any participant === targetId"
         // would match the first cross-framework doc too — instead require ALL participants to be self.
         const matchingDoc = alignmentDocs.find((doc) => {
-          const participants = doc.alignmentParticipants ?? []
+          const participants = doc.extensions?.['ext:opencase']?.alignmentParticipants ?? []
           if (targetId === activeFrameworkId) {
             return participants.length > 0 && participants.every((p) => p.identifier === activeFrameworkId)
           }
diff --git a/apps/editor/src/infrastructure/caseApi/CaseApiClient.ts b/apps/editor/src/infrastructure/caseApi/CaseApiClient.ts
index 8aaa014..8eeebf1 100644
--- a/apps/editor/src/infrastructure/caseApi/CaseApiClient.ts
+++ b/apps/editor/src/infrastructure/caseApi/CaseApiClient.ts
@@ -3,13 +3,25 @@ import type { HttpClient } from './http'
 
 export type OpenCaseCfPackageResponse = { CFPackage: CFPackage }
 
+/**
+ * Shape of the `extensions['ext:opencase']` object as served by the CFDocuments list endpoint
+ * and the management "list frameworks" endpoint (only present when the request sends
+ * X-CASE-EDITOR). Server-side, this object is passed through verbatim — it may contain other
+ * frontend-only keys too (e.g. layout), but these are the ones the editor currently reads here.
+ */
+export type OpenCaseListExtensions = {
+  sourcePackageURI?: string
+  isModifiedFromSource?: boolean
+  alignmentParticipants?: Array<{ identifier?: string; uri: string }>
+}
+
 export type AlignmentFrameworkSummary = {
   sourcedId: string
   title: string
   caseVersion: string
   frameworkType?: string
-  alignmentParticipants?: Array<{ identifier?: string; uri: string }>
   lastChangeDateTime?: string
+  extensions?: { 'ext:opencase'?: OpenCaseListExtensions }
 }
 
 export type OpenCaseManagementCfPackageSummary = {
@@ -37,12 +49,10 @@ export type CfDocumentSummary = {
   adoptionStatus?: string
   lastChangeDateTime?: string
   caseVersion?: string
-  /** URL the framework was imported from, if known (set during import via backend). */
-  sourcePackageURI?: string
-  /** Set (true or false) once a framework has been imported/mirrored; true once it's been locally modified (forked). */
-  isModifiedFromSource?: boolean
   /** Server-level archive flag — independent of CASE adoptionStatus */
   archived?: boolean
+  /** OpenCASE-proprietary data (e.g. sourcePackageURI/isModifiedFromSource for the mirror/fork badge) — only present when the request sends X-CASE-EDITOR. */
+  extensions?: { 'ext:opencase'?: OpenCaseListExtensions }
 }
 
 export class CaseApiClient {
diff --git a/apps/editor/src/ui/home/HomeScreen.tsx b/apps/editor/src/ui/home/HomeScreen.tsx
index 2082f9b..32dc22a 100644
--- a/apps/editor/src/ui/home/HomeScreen.tsx
+++ b/apps/editor/src/ui/home/HomeScreen.tsx
@@ -792,8 +792,8 @@ export default function HomeScreen({
                           frameworkType: doc.frameworkType,
                           adoptionStatus: doc.adoptionStatus,
                         }}
-                        sourcePackageURI={doc.sourcePackageURI}
-                        isModifiedFromSource={doc.isModifiedFromSource}
+                        sourcePackageURI={doc.extensions?.['ext:opencase']?.sourcePackageURI}
+                        isModifiedFromSource={doc.extensions?.['ext:opencase']?.isModifiedFromSource}
                         rightHint={isArchiving ? 'Archiving' : hint}
                         lastChanged={doc.lastChangeDateTime}
                         onClick={() => openRemote(doc.identifier)}
@@ -843,8 +843,8 @@ export default function HomeScreen({
                           frameworkType: doc.frameworkType,
                           adoptionStatus: doc.adoptionStatus,
                         }}
-                        sourcePackageURI={doc.sourcePackageURI}
-                        isModifiedFromSource={doc.isModifiedFromSource}
+                        sourcePackageURI={doc.extensions?.['ext:opencase']?.sourcePackageURI}
+                        isModifiedFromSource={doc.extensions?.['ext:opencase']?.isModifiedFromSource}
                         rightHint={isDeleting ? 'Deleting' : (isRestoring ? 'Restoring' : undefined)}
                         lastChanged={doc.lastChangeDateTime}
                         onDelete={tenantId ? () => handleHardDeleteRequest(doc.identifier, title) : undefined}