+`STARTUP_SUB_SYSCTL`
+-------------------------
+
+### Description
+
+Initializes the sysctl kernel subsystem
+
+### Rank usage
+
+- Rank 1: automatic `SYSCTL_NODE` registration.
+- Rank 2: automatic `SYSCTL_OID` registration.
+- Middle: other manual early registrations.
+- Last: registrations of dummy nodes in the constant nodes to allow extension.
+
+