Unicode "no-op" Character?

[Sławomir Osipiuk via Unicode]

I see there is no such character, which I pretty much expected after Google
didn't help.

 

The original problem I had was solved long ago but the recent article about
watermarking reminded me of it, and my question was mostly out of curiosity.
The task wasn't, strictly speaking, about "padding", but about marking -
injecting "flag" characters at arbitrary points in a string without
affecting the resulting visible text. I think we ended up using ESC, which
is a dumb choice in retrospect, though the whole approach was a bit of a
hack anyway and the process it was for isn't being used anymore.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://unicode.org/pipermail/unicode/attachments/20190622/474752ae/attachment.html>