--- a/browser/devtools/webconsole/test/browser_webconsole_bug_821877_csp_errors.js
+++ b/browser/devtools/webconsole/test/browser_webconsole_bug_821877_csp_errors.js
@@ -7,19 +7,22 @@ const TEST_URI = "https://example.com/br
 const CSP_DEPRECATED_HEADER_MSG = "The X-Content-Security-Policy and X-Content-Security-Report-Only headers will be deprecated in the future. Please use the Content-Security-Policy and Content-Security-Report-Only headers with CSP spec compliant syntax instead.";
 
 function test()
 {
   addTab(TEST_URI);
   browser.addEventListener("load", function onLoad(aEvent) {
     browser.removeEventListener(aEvent.type, onLoad, true);
     openConsole(null, function testCSPErrorLogged (hud) {
-      waitForSuccess({
-        name: "CSP error displayed successfully",
-        validatorFn: function () {
-          return hud.outputNode.textContent.indexOf(CSP_DEPRECATED_HEADER_MSG) > -1;
-        },
-        successFn: finishTest,
-        failureFn: finishTest,
-      });
+      waitForMessages({
+        webconsole: hud,
+        messages: [
+          {
+            name: "Deprecated CSP header error displayed successfully",
+            text: CSP_DEPRECATED_HEADER_MSG,
+            category: CATEGORY_SECURITY,
+            severity: SEVERITY_WARNING
+          },
+        ],
+      }).then(finishTest);
     });
   }, true);
 }

--- a/browser/devtools/webconsole/webconsole.js
+++ b/browser/devtools/webconsole/webconsole.js
@@ -4273,16 +4273,17 @@ var Utils = {
   categoryForScriptError: function Utils_categoryForScriptError(aScriptError)
   {
     switch (aScriptError.category) {
       case "CSS Parser":
       case "CSS Loader":
         return CATEGORY_CSS;
 
       case "Mixed Content Blocker":
+      case "CSP":
         return CATEGORY_SECURITY;
 
       default:
         return CATEGORY_JS;
     }
   },
 
   /**

--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -2368,17 +2368,17 @@ CSPErrorQueue::Add(const char* aMessageN
 }
 
 void
 CSPErrorQueue::Flush(nsIDocument* aDocument)
 {
   for (uint32_t i = 0; i < mErrors.Length(); i++) {
     nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
         "CSP", aDocument,
-        nsContentUtils::eDOM_PROPERTIES,
+        nsContentUtils::eSECURITY_PROPERTIES,
         mErrors[i]);
   }
   mErrors.Clear();
 }
 
 nsresult
 nsDocument::InitCSP(nsIChannel* aChannel)
 {
@@ -2525,32 +2525,21 @@ nsDocument::InitCSP(nsIChannel* aChannel
 
   // While we are supporting both CSP 1.0 and the x- headers, the 1.0 headers
   // take priority.  If any spec-compliant headers are present, the x- headers
   // are ignored, and the spec compliant parser is used.
   bool cspSpecCompliant = (!cspHeaderValue.IsEmpty() || !cspROHeaderValue.IsEmpty());
 
   // If the old header is present, warn that it will be deprecated.
   if (!cspOldHeaderValue.IsEmpty() || !cspOldROHeaderValue.IsEmpty()) {
-    nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
-                                    "CSP", this,
-                                    nsContentUtils::eDOM_PROPERTIES,
-                                    "OldCSPHeaderDeprecated");
-
-    // Additionally log deprecated warning to Web Console.
     mCSPWebConsoleErrorQueue.Add("OldCSPHeaderDeprecated");
 
     // Also, if the new headers AND the old headers were present, warn
     // that the old headers will be ignored.
     if (cspSpecCompliant) {
-      nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
-                                      "CSP", this,
-                                      nsContentUtils::eDOM_PROPERTIES,
-                                      "BothCSPHeadersPresent");
-      // Additionally log to Web Console.
       mCSPWebConsoleErrorQueue.Add("BothCSPHeadersPresent");
     }
   }
 
   // ----- if there's a full-strength CSP header, apply it.
   bool applyCSPFromHeader =
     (( cspSpecCompliant && !cspHeaderValue.IsEmpty()) ||
      (!cspSpecCompliant && !cspOldHeaderValue.IsEmpty()));
@@ -2577,21 +2566,16 @@ nsDocument::InitCSP(nsIChannel* aChannel
 
   // ----- if there's a report-only CSP header, apply it
   if (( cspSpecCompliant && !cspROHeaderValue.IsEmpty()) ||
       (!cspSpecCompliant && !cspOldROHeaderValue.IsEmpty())) {
     // post a warning and skip report-only CSP when both read only and regular
     // CSP policies are present since CSP only allows one policy and it can't
     // be partially report-only.
     if (applyAppDefaultCSP || applyCSPFromHeader) {
-      nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
-                                      "CSP", this,
-                                      nsContentUtils::eDOM_PROPERTIES,
-                                      "ReportOnlyCSPIgnored");
-      // Additionally log to Web Console.
       mCSPWebConsoleErrorQueue.Add("ReportOnlyCSPIgnored");
 #ifdef PR_LOGGING
       PR_LOG(gCspPRLog, PR_LOG_DEBUG,
               ("Skipped report-only CSP init for document %p because another, enforced policy is set", this));
 #endif
     } else {
       // we can apply the report-only policy because there's no other CSP
       // applied.

--- a/dom/locales/en-US/chrome/dom/dom.properties
+++ b/dom/locales/en-US/chrome/dom/dom.properties
@@ -78,17 +78,16 @@ FullScreenDeniedLostWindow=Request for f
 FullScreenDeniedSubDocFullScreen=Request for full-screen was denied because a subdocument of the document requesting full-screen is already full-screen.
 FullScreenDeniedNotDescendant=Request for full-screen was denied because requesting element is not a descendant of the current full-screen element.
 FullScreenDeniedNotFocusedTab=Request for full-screen was denied because requesting element is not in the currently focused tab.
 FullScreenDeniedContentOnly=Request for full-screen was denied because requesting element is in the chrome document and the fullscreen API is configured for content only.
 RemovedFullScreenElement=Exited full-screen because full-screen element was removed from document.
 FocusedWindowedPluginWhileFullScreen=Exited full-screen because windowed plugin was focused.
 HTMLSyncXHRWarning=HTML parsing in XMLHttpRequest is not supported in the synchronous mode.
 InvalidRedirectChannelWarning=Unable to redirect to %S because the channel doesn't implement nsIWritablePropertyBag2.
-ReportOnlyCSPIgnored=Report-only CSP policy will be ignored because there are other non-report-only CSP policies applied.
 ResponseTypeSyncXHRWarning=Use of XMLHttpRequest's responseType attribute is no longer supported in the synchronous mode in window context.
 WithCredentialsSyncXHRWarning=Use of XMLHttpRequest's withCredentials attribute is no longer supported in the synchronous mode in window context.
 TimeoutSyncXHRWarning=Use of XMLHttpRequest's timeout attribute is not supported in the synchronous mode in window context.
 JSONCharsetWarning=An attempt was made to declare a non-UTF-8 encoding for JSON retrieved using XMLHttpRequest. Only UTF-8 is supported for decoding JSON.
 # LOCALIZATION NOTE: Do not translate AudioBufferSourceNode
 MediaBufferSourceNodeResampleOutOfMemory=Insufficient memory to resample the AudioBufferSourceNode for playback.
 # LOCALIZATION NOTE: Do not translate decodeAudioData.
 MediaDecodeAudioDataUnknownContentType=The buffer passed to decodeAudioData contains an unknown content type.
@@ -123,18 +122,14 @@ MozSliceWarning=Use of mozSlice on the B
 # LOCALIZATION NOTE: Do not translate "Components"
 ComponentsWarning=The Components object is deprecated. It will soon be removed.
 PluginHangUITitle=Warning: Unresponsive plugin
 PluginHangUIMessage=%S may be busy, or it may have stopped responding. You can stop the plugin now, or you can continue to see if the plugin will complete.
 PluginHangUIWaitButton=Continue
 PluginHangUIStopButton=Stop plugin
 # LOCALIZATION NOTE: Do not translate "mozHidden", "mozVisibilityState", "hidden", or "visibilityState"
 PrefixedVisibilityApiWarning='mozHidden' and 'mozVisibilityState' are deprecated.  Please use the unprefixed 'hidden' and 'visibilityState' instead.
-# LOCALIZATION NOTE: Do not translate "X-Content-Security-Policy", "X-Content-Security-Policy-Report-Only",  "Content-Security-Policy" or "Content-Security-Policy-Report-Only"
-OldCSPHeaderDeprecated=The X-Content-Security-Policy and X-Content-Security-Report-Only headers will be deprecated in the future. Please use the Content-Security-Policy and Content-Security-Report-Only headers with CSP spec compliant syntax instead.
-# LOCALIZATION NOTE: Do not translate "X-Content-Security-Policy/Report-Only" or "Content-Security-Policy/Report-Only"
-BothCSPHeadersPresent=This site specified both an X-Content-Security-Policy/Report-Only header and a Content-Security-Policy/Report-Only header. The X-Content-Security-Policy/Report-Only header(s) will be ignored.
 # LOCALIZATION NOTE: Do not translate "NodeIterator" or "detach()".
 NodeIteratorDetachWarning=Calling detach() on a NodeIterator no longer has an effect.
 # LOCALIZATION NOTE: Do not translate "Mozilla Audio Data API" and "Web Audio API".
 MozAudioDataWarning=The Mozilla Audio Data API is deprecated.  Please use the Web Audio API instead.
 # LOCALIZATION NOTE: Do not translate "LenientThis" and "this"
 LenientThisWarning=Ignoring get or set of property that has [LenientThis] because the "this" object is incorrect.

--- a/dom/locales/en-US/chrome/security/security.properties
+++ b/dom/locales/en-US/chrome/security/security.properties
@@ -1,2 +1,10 @@
+# Mixed Content Blocker
 BlockMixedDisplayContent = Blocked loading mixed display content "%1$S"
 BlockMixedActiveContent = Blocked loading mixed active content "%1$S"
+
+# CSP
+ReportOnlyCSPIgnored=Report-only CSP policy will be ignored because there are other non-report-only CSP policies applied.
+# LOCALIZATION NOTE: Do not translate "X-Content-Security-Policy", "X-Content-Security-Policy-Report-Only",  "Content-Security-Policy" or "Content-Security-Policy-Report-Only"
+OldCSPHeaderDeprecated=The X-Content-Security-Policy and X-Content-Security-Report-Only headers will be deprecated in the future. Please use the Content-Security-Policy and Content-Security-Report-Only headers with CSP spec compliant syntax instead.
+# LOCALIZATION NOTE: Do not translate "X-Content-Security-Policy/Report-Only" or "Content-Security-Policy/Report-Only"
+BothCSPHeadersPresent=This site specified both an X-Content-Security-Policy/Report-Only header and a Content-Security-Policy/Report-Only header. The X-Content-Security-Policy/Report-Only header(s) will be ignored.