Unicode "no-op" Character?

[Richard Wordingham via Unicode]

On Sat, 22 Jun 2019 23:56:11 +0000
Shawn Steele via Unicode <unicode at unicode.org> wrote:

> Assuming you were using any of those characters as "markup", how
> would you know when they were intentionally in the string and not
> part of your marking system?

If they're conveying an invisible message, one would have to strip out
original ZWNBSP/WJ/ZWSP that didn't affect line-breaking.  The weak
point is that that assumes that line-break opportunities are
well-defined.  For example, they aren't for SE Asian text.

Richard.