chromium/third_party/blink/web_tests/inspector-protocol/css/resources/set-position-try-rule-style-text.css

#anchor {
    anchor-name: --fallback;
}

#anchored {
    position: absolute;
    position-try-fallbacks: --fallback;
}

@position-try --fallback {
    bottom: anchor(--anchor bottom);
    right: anchor(--anchor right);
}