I'm trying out the <link rel="dns-prefetch"> and <link rel="preconnect"> tags and I'm trying to see whether they help for my site. I can't find any online resources about how verify if these hints are working using browser dev tools, extensions, or other software. It seems like you just evaluate whether they may be useful to you based on some criteria and then drop them in and hope for the best.
In my case, I have a single page app that renders the entire contents of the <body> in the browser, so the browser can't really scan the initial HTML to lookahead for domains to resolve so it seemed like this might be useful for me.
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