U+E0000..U+E007F
UNICODE TAG CHARACTER

Completely invisible. Used to smuggle hidden text or prompt injections.

Codepoint

U+E0000..U+E007F

Short

TAG

Group

tag-characters

Class

invisible

Default

removed

Replaced by

removed, no substitute

Codepoints

128

What it is

A block of 128 codepoints that mirror printable ASCII and render as absolutely nothing. They were introduced for language tagging, that use was deprecated, and what remains is a complete invisible alphabet.

Where it comes from

Almost always deliberately. Because the block mirrors ASCII one to one, any string of ordinary text can be re-encoded into tag characters and pasted inside visible text, where it survives copying and shows up in no editor. It is the standard vehicle for hidden payloads, watermarks and prompt injections aimed at language models.

When it belongs

Never, in any text a person wrote. This is the one place in the catalog where there is no legitimate use to protect and therefore no context guard: the block was deprecated for its original purpose, and everything that remains is concealment.

What TraceFree PRO does with it

Context guards can only ever make a cleanup gentler, never sharper. A rule saying “always remove” does not override them.

How to remove it

In TraceFree PRO, turn on the clipboard watcher and copy the text. On the command line:

tracefree clean --backup document.txt
pbpaste | tracefree clean | pbcopy

Report without changing anything — exit code 1 on findings, so it works in CI:

tracefree check -r ./docs

How to write it

This page never prints the character itself, only ways of writing it. A page about invisible characters that contained invisible characters would be unreviewable — and that is the problem the program exists to solve.

Try it on your own text

Paste anything into the browser demo and see what is in it. Same engine as the app, running entirely on your device — nothing is uploaded.

Try it