EventSource has no need to set Cache-Control

That is handled directly by Fetch based on the cache mode.

This also cross-references a remaining instance of Cache-Control in the
specification, so that it doesn’t look like it is not used.

source

@@ -24073,8 +24073,8 @@ interface <dfn>HTMLImageElement</dfn> : <span>HTMLElement</span> {
   memory).
   User agents must remove entries in the <span>list of available images</span> as appropriate
   given higher-layer caching semantics for the resource (e.g. the HTTP `<code
-  data-x="">Cache-Control</code>` response header) when the <span>ignore higher-layer caching</span>
-  flag is unset.</p>
+  data-x="http-cache-control">Cache-Control</code>` response header) when the <span>ignore
+  higher-layer caching</span> flag is unset.</p>
 
   <p class="note">The <span>list of available images</span> is intended to enable synchronous
   switching when changing the <code data-x="attr-img-src">src</code> attribute to a URL that has
@@ -91325,11 +91325,8 @@ dictionary <dfn>EventSourceInit</dfn> {
    data-x="http-accept">Accept</code>`/`<code>text/event-stream</code>` in <var>request</var>'s
    <span data-x="concept-request-header-list">header list</span>.</p></li>
 
-   <li><p>User agents should <span data-x="concept-header-list-set">set</span> `<code
-   data-x="http-cache-control">Cache-Control</code>`/`<code data-x="">no-cache</code>` in
-   <var>request</var>'s <span data-x="concept-request-header-list">header list</span> and set
-   <var>request</var>'s <span data-x="concept-request-cache-mode">cache mode</span> to "<code
-   data-x="">no-store</code>".</p></li>
+   <li><p>Set <var>request</var>'s <span data-x="concept-request-cache-mode">cache mode</span> to
+   "<code data-x="">no-store</code>".</p></li>
 
    <li><p>Set <code>EventSource</code> object's <span
    data-x="concept-event-stream-request">request</span> to <var>request</var>.</p></li>