From e3f537db722a7ed0d427e2d39ff87d1e629fe0cb Mon Sep 17 00:00:00 2001
From: John Delaney <40465606+johnivdel@users.noreply.github.com>
Date: Mon, 23 May 2022 14:23:24 -0400
Subject: [PATCH] Make the attributionsrc ping optional

Resolves https://github.com/WICG/conversion-measurement-api/issues/378
---
 EVENT.md | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/EVENT.md b/EVENT.md
index 10fd8b454..91b55adcc 100644
--- a/EVENT.md
+++ b/EVENT.md
@@ -109,6 +109,12 @@ Protocol](https://github.com/brave/brave-browser/wiki/Security-and-privacy-model
 Attribution sources are events which future triggers can be attributed to. There
 are two types of attribution sources, `navigation` sources and `event` sources.
 
+Sources are registered by returning a new HTTP response header on requests which
+eligible for attribution. A request is eligible as long as it has the
+`Attribution-Reporting-Eligible` request header.
+
+
+
 `navigation` sources are registered via clicks on anchor tags:
 ```html
 <a href="https://advertiser.example/landing"
@@ -143,15 +149,19 @@ window.fetch("https://adtech.example/attribution_source?my_ad_id=123",
              { headers });
 ```
 
-The `<a>`, `<img>`, and `window.open` mechanisms will cause the browser to
-initiate a `keepalive` fetch request to the URL indicated by `attributionsrc`.
+Specifying a URL value for `attributionsrc` within `<a>`, `<img>`, or `window.open`
+will cause the browser to initiate a `keepalive` fetch request that is eligible for
+attribution.
+
+When the `attributionsrc` attribute is present in these surfaces/APIs, both with and
+without a value, existing requests made via `src`, `href`, or `window.open` will
+include the `Attribution-Reporting-Eligible` request header. Each of these
+requests will be able to register attribution sources.
 
-Response headers will be processed for any request that includes the
-`Attribution-Reporting-Eligible` request header, not just ones initiated via
-`window.fetch`. For example, responses will also be processed for
-`XmlHttpRequest` if the header was present on the corresponding request.
+Other requests APIs which allow specifying header, such as `XmlHttpRequest`, are
+able to use this as well.
 
-The response to this request will configure the API. The browser will expect
+The response to these requests will configure the API. The browser will expect
 data in a new JSON HTTP header `Attribution-Reporting-Register-Source` which
 configures the API: