diff --git a/webextensions/api/declarativeNetRequest.json b/webextensions/api/declarativeNetRequest.json
index a72d9048b25cec..92dd8f99253fa8 100644
--- a/webextensions/api/declarativeNetRequest.json
+++ b/webextensions/api/declarativeNetRequest.json
@@ -455,6 +455,26 @@
               }
             }
           },
+          "json": {
+            "__compat": {
+              "support": {
+                "chrome": {
+                  "version_added": false
+                },
+                "edge": "mirror",
+                "firefox": {
+                  "version_added": "138",
+                  "notes": "The \"json\" property is supported from Firefox 135, but requests of this type are only available from Firefox 138."
+                },
+                "firefox_android": "mirror",
+                "opera": "mirror",
+                "safari": {
+                  "version_added": false
+                },
+                "safari_ios": "mirror"
+              }
+            }
+          },
           "main_frame": {
             "__compat": {
               "support": {
diff --git a/webextensions/api/webRequest.json b/webextensions/api/webRequest.json
index 283bf9e1289c47..c6adcf8530deb0 100644
--- a/webextensions/api/webRequest.json
+++ b/webextensions/api/webRequest.json
@@ -398,6 +398,26 @@
               }
             }
           },
+          "json": {
+            "__compat": {
+              "support": {
+                "chrome": {
+                  "version_added": false
+                },
+                "edge": "mirror",
+                "firefox": {
+                  "version_added": "138",
+                  "notes": "The \"json\" property is supported from Firefox 135, but requests of this type are only available from Firefox 138."
+                },
+                "firefox_android": "mirror",
+                "opera": "mirror",
+                "safari": {
+                  "version_added": false
+                },
+                "safari_ios": "mirror"
+              }
+            }
+          },
           "main_frame": {
             "__compat": {
               "support": {