diff --git a/toolkit/components/resistfingerprinting/RFPHelper.sys.mjs b/toolkit/components/resistfingerprinting/RFPHelper.sys.mjs
index b0e5d95eb55790efc068d04ae3f4401c8f390e8e..eee0a60d4acb0e77f209de9ee431e379b45fe311 100644
--- a/toolkit/components/resistfingerprinting/RFPHelper.sys.mjs
+++ b/toolkit/components/resistfingerprinting/RFPHelper.sys.mjs
@@ -376,6 +376,8 @@ class _RFPHelper {
       contentPrincipal.isSystemPrincipal ||
       // ... about: URIs EXCEPT about:blank
       (currentURI.schemeIs("about") && currentURI.filePath !== "blank") ||
+      // ... source code
+      currentURI.schemeIs("view-source") ||
       // ... browser extensions
       contentPrincipal.addonPolicy
     );