safari
why is there a red shield symbol on my safari tab?
MacBook Air 13″, macOS 12.2
Probably just a website favicon. Favicons are small images used by websites to identify themselves on the tab bar.
Its not A Safari icon specifically, but one from the website. In the case of the Apple forums it may have been a glitch from a previous website you visited in that tab or just an internal problem with Apple’s own Apple favicon.
I can’t reproduce it, but in general its not something to worry about.