Add comments on compat files

To prevent further confusion.

Bug: 258029505
Test: manual
Change-Id: Iaa145e4480833a224b1a07fc68adb7d3e8a36e4b
diff --git a/private/compat/29.0/29.0.cil b/private/compat/29.0/29.0.cil
index 5dba020..7315687 100644
--- a/private/compat/29.0/29.0.cil
+++ b/private/compat/29.0/29.0.cil
@@ -14,6 +14,7 @@
 (type sysfs_mac_address)
 (type wificond_service)
 
+;; mapping information from ToT policy's types to 29.0 policy's types.
 (expandtypeattribute (accessibility_service_29_0) true)
 (expandtypeattribute (account_service_29_0) true)
 (expandtypeattribute (activity_service_29_0) true)
diff --git a/private/compat/29.0/29.0.compat.cil b/private/compat/29.0/29.0.compat.cil
index ccd9d1a..0bb2ae8 100644
--- a/private/compat/29.0/29.0.compat.cil
+++ b/private/compat/29.0/29.0.compat.cil
@@ -1,3 +1,7 @@
+;; complement CIL file for compatibility between ToT policy and 29.0 vendors.
+;; will be compiled along with other normal policy files, on 29.0 vendors.
+;;
+
 (typeattribute vendordomain)
 (typeattributeset vendordomain ((and (domain) ((not (coredomain))))))
 (allow vendordomain self (netlink_route_socket (nlmsg_readpriv)))
diff --git a/private/compat/29.0/29.0.ignore.cil b/private/compat/29.0/29.0.ignore.cil
index 1079046..e40888d 100644
--- a/private/compat/29.0/29.0.ignore.cil
+++ b/private/compat/29.0/29.0.ignore.cil
@@ -1,6 +1,6 @@
-;; new_objects - a collection of types that have been introduced that have no
-;;   analogue in older policy.  Thus, we do not need to map these types to
-;;   previous ones.  Add here to pass checkapi tests.
+;; new_objects - a collection of types that have been introduced with ToT policy
+;;   that have no analogue in 29.0 policy.  Thus, we do not need to map
+;;   these types to previous ones.  Add here to pass checkapi tests.
 (type new_objects)
 (typeattribute new_objects)
 (typeattributeset new_objects