Normally when you visit a redirected MW page e.g. [[ https://en.wikipedia.org/wiki/Beatles | wp:Beatles ]], the nifty `#contentSub` div shows a helpful (Redirected from [[OldPage]]) `redirectedfrom` message.
Redirects to Flow pages don't show this indicator, e.g. https://www.mediawiki.org/wiki/Talk:Flow_Portal silently redirects to a Flow page with no indication except that the H1 title doesn't match the title in the URL.
Core's `showRedirecteFromHeader()` in Article.php gives you this "for free", but Flow's View.php isn't an Article. Somehow the JsonSchema content type handles this correctly, see [[ https://meta.wikimedia.org/wiki/User:S_Page_%28WMF%29/TestSchemaRedirect | test redirect to schema on meta]]; maybe class WikitextContent is doing the work.