diff --git a/eo-missions/aeolus/catalog.json b/eo-missions/aeolus/catalog.json
index db4b4cdd7..70a6067d8 100644
--- a/eo-missions/aeolus/catalog.json
+++ b/eo-missions/aeolus/catalog.json
@@ -50,9 +50,15 @@
       "rel": "self",
       "href": "https://esa-earthcode.github.io/open-science-catalog-metadata/eo-missions/aeolus/catalog.json",
       "type": "application/json"
+    },
+    {
+      "rel": "child",
+      "href": "../../products/test-product/collection.json",
+      "type": "application/json",
+      "title": "Test Product"
     }
   ],
   "updated": "2024-08-27T17:27:42.171831Z",
   "keywords": [],
   "title": "AEOLUS"
-}
\ No newline at end of file
+}
diff --git a/products/catalog.json b/products/catalog.json
index be84321f5..d38fe057a 100644
--- a/products/catalog.json
+++ b/products/catalog.json
@@ -1820,6 +1820,12 @@
       "rel": "self",
       "href": "https://esa-earthcode.github.io/open-science-catalog-metadata/products/catalog.json",
       "type": "application/json"
+    },
+    {
+      "rel": "child",
+      "href": "./test-product/collection.json",
+      "type": "application/json",
+      "title": "Test Product"
     }
   ],
   "updated": "2024-09-12T20:32:22.975110Z",
diff --git a/products/test-product/collection.json b/products/test-product/collection.json
new file mode 100644
index 000000000..2c8af32f0
--- /dev/null
+++ b/products/test-product/collection.json
@@ -0,0 +1,81 @@
+{
+  "id": "test-product",
+  "title": "Test Product",
+  "created": "2025-05-06T14:57:46Z",
+  "type": "Collection",
+  "osc:type": "product",
+  "stac_version": "1.0.0",
+  "stac_extensions": [],
+  "description": "Description",
+  "keywords": [],
+  "license": "various",
+  "extent": {
+    "spatial": {
+      "bbox": []
+    },
+    "temporal": {
+      "interval": [
+        [
+          "2025-05-05T00:00:00Z",
+          "2025-05-08T23:59:59Z"
+        ]
+      ]
+    }
+  },
+  "providers": [],
+  "summaries": [],
+  "assets": {},
+  "links": [
+    {
+      "href": "../../projects/3d-earth/collection.json",
+      "title": "3D-EARTH",
+      "type": "application/json",
+      "rel": "related"
+    },
+    {
+      "href": "../../themes/atmosphere/catalog.json",
+      "title": "Atmosphere",
+      "type": "application/json",
+      "rel": "related"
+    },
+    {
+      "href": "../../variables/13-ch4-delta/catalog.json",
+      "title": "(13)CH4 delta",
+      "type": "application/json",
+      "rel": "related"
+    },
+    {
+      "href": "../../eo-missions/aeolus/catalog.json",
+      "title": "AEOLUS",
+      "type": "application/json",
+      "rel": "related"
+    }
+  ],
+  "updated": "2025-05-06T14:57:58Z",
+  "osc:status": "planned",
+  "osc:project": "3d-earth",
+  "osc:region": "global",
+  "osc:variables": [
+    "13-ch4-delta"
+  ],
+  "osc:missions": [
+    "aeolus"
+  ],
+  "osc:experiment": "Test",
+  "themes": [
+    {
+      "scheme": "OSC:SCHEME:THEMES",
+      "concepts": [
+        {
+          "id": "atmosphere"
+        }
+      ]
+    }
+  ],
+  "cf:parameter": [
+    {
+      "name": "",
+      "unit": ""
+    }
+  ]
+}
diff --git a/projects/3d-earth/collection.json b/projects/3d-earth/collection.json
index b4ab27be3..e26baaaef 100644
--- a/projects/3d-earth/collection.json
+++ b/projects/3d-earth/collection.json
@@ -48,6 +48,12 @@
       "href": "../../themes/solid-earth/catalog.json",
       "type": "application/json",
       "title": "Theme: Solid Earth"
+    },
+    {
+      "rel": "child",
+      "href": "../../products/test-product/collection.json",
+      "type": "application/json",
+      "title": "Test Product"
     }
   ],
   "stac_extensions": [
diff --git a/projects/catalog.json b/projects/catalog.json
index 115efca62..218189947 100644
--- a/projects/catalog.json
+++ b/projects/catalog.json
@@ -1106,6 +1106,12 @@
       "rel": "self",
       "href": "https://esa-earthcode.github.io/open-science-catalog-metadata/projects/catalog.json",
       "type": "application/json"
+    },
+    {
+      "rel": "child",
+      "href": "./demo-project/collection.json",
+      "type": "application/json",
+      "title": "Demo Project"
     }
   ],
   "updated": "2024-09-12T20:32:23.037110Z",
diff --git a/projects/demo-project/collection.json b/projects/demo-project/collection.json
new file mode 100644
index 000000000..f2d9b11d5
--- /dev/null
+++ b/projects/demo-project/collection.json
@@ -0,0 +1,6 @@
+{
+  "id": "demo-project",
+  "title": "Demo Project",
+  "type": "Collection",
+  "osc:type": "project"
+}
diff --git a/themes/atmosphere/catalog.json b/themes/atmosphere/catalog.json
index 8ef0af75f..6a88507b0 100644
--- a/themes/atmosphere/catalog.json
+++ b/themes/atmosphere/catalog.json
@@ -295,9 +295,15 @@
       "rel": "self",
       "href": "https://esa-earthcode.github.io/open-science-catalog-metadata/themes/atmosphere/catalog.json",
       "type": "application/json"
+    },
+    {
+      "rel": "child",
+      "href": "../../products/test-product/collection.json",
+      "type": "application/json",
+      "title": "Test Product"
     }
   ],
   "updated": "2024-08-27T17:27:42.198831Z",
   "keywords": [],
   "title": "Atmosphere"
-}
\ No newline at end of file
+}
diff --git a/variables/13-ch4-delta/catalog.json b/variables/13-ch4-delta/catalog.json
index 9e899805a..7ce18b9dd 100644
--- a/variables/13-ch4-delta/catalog.json
+++ b/variables/13-ch4-delta/catalog.json
@@ -32,6 +32,12 @@
       "href": "../../themes/atmosphere/catalog.json",
       "type": "application/json",
       "title": "Theme: Atmosphere"
+    },
+    {
+      "rel": "child",
+      "href": "../../products/test-product/collection.json",
+      "type": "application/json",
+      "title": "Test Product"
     }
   ],
   "stac_extensions": [
@@ -50,4 +56,4 @@
   "updated": "2024-08-27T17:27:42.203831Z",
   "keywords": [],
   "title": "(13)CH4 delta"
-}
\ No newline at end of file
+}