Zero-width and invisible
INVISIBLE PLUS (U+2064)
The invisible addition sign used between the parts of a mixed fraction — the "and" in "one and a half".
- Codepoint
U+2064- Category
- Zero-width and invisible
- Removed by default
- Yes
- Governing option
- No option needed
- Can be load-bearing
- No
Where it comes from
MathML and equation editors, copied into prose as plain text.
Why it matters
It is invisible, it is not whitespace, and it completes the four-codepoint alphabet that zero-width payload tools favour when U+200B is filtered.
Before and after
One and a half, with the invisible plus that made it one number.
The character is shown as a labelled chip so you can see where it sits. In your text it draws nothing at all.
When it is legitimate
Inside a mixed-number expression in MathML.
How to remove it
The default pass removes it, like its three neighbours. Nothing you can see changes: the digits were already rendered side by side.
Is it an AI watermark?
Used to hide data — not a watermark
No. Maths markup. Its presence in prose points at a copy-paste from an equation, or at a tool that chose it deliberately.
A known carrier for deliberately hidden payloads. Someone put it there on purpose, which is a different question from who wrote the words.
Questions
Does removing it change the number?
In rendered plain text the digits were already ambiguous. Removing the operator does not change what is displayed; if the maths matters, keep the MathML.
Why is it removed without asking?
Because outside MathML it is an invisible character with no job, and every invisible character with no job is a hiding place.
Check your own text
Paste anything into the cleaner to see every hidden character it contains, with position, codepoint and what happens to each one. Nothing is uploaded.