Index: extensions/common/api/runtime.json
--- extensions/common/api/runtime.json.orig
+++ extensions/common/api/runtime.json
@@ -89,6 +89,7 @@
             {"name": "cros", "description": "Specifies the Chrome operating system."},
             {"name": "linux", "description": "Specifies the Linux operating system."},
             {"name": "openbsd", "description": "Specifies the OpenBSD operating system."},
+            {"name": "freebsd", "description": "Specifies the FreeBSD operating system."},
             {"name": "fuchsia", "description": "Specifies the Fuchsia operating system."}
         ]
       },