diff --git a/webextensions/manifest/content_security_policy.json b/webextensions/manifest/content_security_policy.json
index bb1e092dbdbca6..aa984f2ce1d590 100644
--- a/webextensions/manifest/content_security_policy.json
+++ b/webextensions/manifest/content_security_policy.json
@@ -69,7 +69,7 @@
               },
               "edge": "mirror",
               "firefox": {
-                "version_added": false
+                "version_added": "154"
               },
               "firefox_android": "mirror",
               "opera": "mirror",
diff --git a/webextensions/manifest/sandbox.json b/webextensions/manifest/sandbox.json
new file mode 100644
index 00000000000000..a10f4bed24bc7a
--- /dev/null
+++ b/webextensions/manifest/sandbox.json
@@ -0,0 +1,65 @@
+{
+  "webextensions": {
+    "manifest": {
+      "sandbox": {
+        "__compat": {
+          "support": {
+            "chrome": {
+              "version_added": "21"
+            },
+            "edge": "mirror",
+            "firefox": {
+              "version_added": "154"
+            },
+            "firefox_android": "mirror",
+            "opera": "mirror",
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": "mirror"
+          }
+        },
+        "content_security_policy": {
+          "__compat": {
+            "support": {
+              "chrome": {
+                "version_added": "21",
+                "notes": "Only available in Manifest V2. From Manifest V3, use `content_security_policy.sandbox` instead."
+              },
+              "edge": "mirror",
+              "firefox": {
+                "version_added": "154",
+                "notes": "Only available in Manifest V2. From Manifest V3, use `content_security_policy.sandbox` instead."
+              },
+              "firefox_android": "mirror",
+              "opera": "mirror",
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": "mirror"
+            }
+          }
+        },
+        "pages": {
+          "__compat": {
+            "support": {
+              "chrome": {
+                "version_added": "≤22"
+              },
+              "edge": "mirror",
+              "firefox": {
+                "version_added": "154"
+              },
+              "firefox_android": "mirror",
+              "opera": "mirror",
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": "mirror"
+            }
+          }
+        }
+      }
+    }
+  }
+}