replay: iframe srcdoc block (#7046)

Co-authored-by: Shana Matthews <[email protected]>
Co-authored-by: getsantry[bot] <66042841+getsantry[bot]@users.noreply.github.com>

Author: 3 people

src/platforms/javascript/common/session-replay/troubleshooting.mdx

@@ -44,6 +44,12 @@ Another reason you might not see the body is if the format is not supported. We
 
 More details about this feature can be found in the <PlatformLink to="/session-replay/configuration/">configuration page</PlatformLink>.
 
+## Text in the iframe isn't masked
+
+Our masking logic doesn't run on iframe content that's provided using the `srcdoc` attribute, rather than loaded in via `src`.
+
+To hide this content, block the iframe, as described in our Session Replay <PlatformLink to="/session-replay/privacy/#blocking">Privacy</PlatformLink> docs.
+
 ## Replay on My Browser Extension Doesn't Work
 
 This is not a supported use-case. The replay package is built to work on a website and not as an externally-loaded script via browser extension or other mechanism. In fact, Sentry's Session Replay product can help developers find out when a third-party Chrome extension causes otherwise hard to debug or reproduce issues with their website.