The Tags block is a special Unicode range, U+E0000 to U+E007F, that can encode ASCII-like text without displaying normally. In practice, it can carry hidden characters that survive copy, paste, or message transport while remaining nearly invisible to a human reader. Security teams care about it because attackers can use it for obfuscation: keywords, brand names, or commands may look intact on screen but be fragmented or altered at the raw-text level.
In cyber security, this matters most in phishing, spam filtering, and content inspection pipelines. A rule that matches only raw bytes may miss a lure, while a filter that normalizes text too early or blocks all unusual Unicode may create false positives. Good defenses compare normalized and rendered text, flag unusual code points as anomalies, and inspect messages before and after conversion. The Tags block is not inherently malicious, but it is a useful place to hide intent.