diff --git a/api/FileSystemFileHandle.json b/api/FileSystemFileHandle.json
index 6e683a787322e0..85106a334a970e 100644
--- a/api/FileSystemFileHandle.json
+++ b/api/FileSystemFileHandle.json
@@ -73,6 +73,39 @@
             "standard_track": true,
             "deprecated": false
           }
+        },
+        "mode": {
+          "__compat": {
+            "description": "<code>mode</code> option",
+            "support": {
+              "chrome": {
+                "version_added": "121"
+              },
+              "chrome_android": "mirror",
+              "edge": "mirror",
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": "mirror",
+              "ie": {
+                "version_added": false
+              },
+              "oculus": "mirror",
+              "opera": "mirror",
+              "opera_android": "mirror",
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": "mirror",
+              "samsunginternet_android": "mirror",
+              "webview_android": "mirror"
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": false,
+              "deprecated": false
+            }
+          }
         }
       },
       "createWritable": {
@@ -110,6 +143,41 @@
             "standard_track": true,
             "deprecated": false
           }
+        },
+        "mode": {
+          "__compat": {
+            "description": "<code>mode</code> option",
+            "support": {
+              "chrome": {
+                "version_added": "121"
+              },
+              "chrome_android": "mirror",
+              "edge": "mirror",
+              "firefox": {
+                "version_added": false
+              },
+              "firefox_android": "mirror",
+              "ie": {
+                "version_added": false
+              },
+              "oculus": "mirror",
+              "opera": "mirror",
+              "opera_android": "mirror",
+              "safari": {
+                "version_added": false
+              },
+              "safari_ios": "mirror",
+              "samsunginternet_android": "mirror",
+              "webview_android": {
+                "version_added": false
+              }
+            },
+            "status": {
+              "experimental": true,
+              "standard_track": false,
+              "deprecated": false
+            }
+          }
         }
       },
       "getFile": {