The very first lesson every web hacker learns: the browser shows you the page, but it also hands you the source. Nothing rendered in your browser is ever truly hidden — it all arrived as text you can read.
Somewhere in this page's HTML is a flag in the form flag{...}. It is not visible on screen — it's sitting in the source.
Open the page source: right-click anywhere → View Page Source, or press Ctrl+U (Windows) / Cmd+Option+U (Mac). Then search the text for flag{.
Why it matters: never put secrets, API keys, or "hidden" admin links in front-end code. If the browser can run it, an attacker can read it.