diff --git a/website/content/en/releases/13.0R/relnotes.adoc b/website/content/en/releases/13.0R/relnotes.adoc
--- a/website/content/en/releases/13.0R/relnotes.adoc
+++ b/website/content/en/releases/13.0R/relnotes.adoc
@@ -157,6 +157,10 @@
 [[kernel-general]]
 === General Kernel Changes
 
+Processes that attach to a {{< manpage "jail" "8" >}} will now completely rebase their {{< manpage "cpuset" "1" >}} onto the jail's cpuset.
+Notably, if a process had been assigned a numbered cpuset then it will be assigned a new numbered set that is the combination of CPUs
+allowed to the attaching process and the jail.
+Processes belonging to the superuser will implicitly widen their CPU mask as needed if they share no CPUs in common with the jail.
 
 [[drivers]]
 == Devices and Drivers