review

EVENT.md

@@ -980,9 +980,10 @@ were reported.
 
 In order to achieve the privacy goals listed above the API has various rate limits, which can be found [here](https://github.com/WICG/attribution-reporting-api/blob/main/params/chromium-params.md) for Chromium.
 
-Note: Browsers may choose to allow separate rate limits for the embedded site 
-for specific use cases (for example, [AMP](https://amp.dev) pages rendered by
-an AMP cache/viewer provider).
+Note: Browsers may choose to allow separate limits, e.g. storage limit,
+rate-limits, and destination limits, for the embedded site/origin for specific
+use cases (for example, [AMP](https://amp.dev) pages rendered by an AMP
+cache/viewer provider).
 
 ### Trigger Data
 

index.bs

@@ -1869,10 +1869,14 @@ To <dfn>check if cookie-based debugging is allowed</dfn> given a
 
 <h3 algorithm id="obtaining-context-origin">Obtaining context origin</h3>
 
-To obtain the <dfn export for=node>context origin</dfn> of a [=node=] |node|, return |node|'s [=node navigable=]'s
-[=navigable/top-level traversable=]'s [=navigable/active document=]'s [=origin=].
+To obtain the <dfn export for=node>context origin</dfn> of a [=node=] |node|:
 
-Note: The user agent MAY return the embedded origin for specific use cases.
+1. Optionally, return the embedded origin if it exists.
+1. Return |node|'s [=node navigable=]'s [=navigable/top-level traversable=]'s
+    [=navigable/active document=]'s [=origin=].
+
+Note: The user agent MAY return the embedded origin to allow separate limits
+for specific use cases.
 
 <h3 id="obtaining-randomized-response">Obtaining a randomized response</h3>