I tried pre tags in the writeup but must not have pasted it in and previewed correctly.
PerlMonks engine automatically replaces all symbols not representable in ASCII by their HTML entity codes: ы → &#1099;. The <code> are special non-HTML tags that don't allow HTML entities inside them to be interpreted, but the transformation still takes place. (How did I write that? <tt>ы</tt> &rightarrow; <c>ы</c> and let PerlMonks make the replacement, knowing that the entity code inside <tt>...</tt> will be interpreted back into ы, while the one inside <c>...</c> won't. How did I write what I just wrote? Lots of &lt;s and <code> = <c> equivalence.)
It is the unicode replacement character: U+FFFD.
The replacement character is what happens when your terminal emulator tries to decode KOI8-R-encoded bytes as UTF-8 and fails. The actual output of diff contains both KOI8-R- and UTF-8- encoded bytes and can be decoded as KOI8-R: 
$ diff 1.file 3.file | iconv -f koi8-r
1c1
< Привет
---
> п÷я─п╦п╡п╣я┌

In reply to Re^5: create clone script for utf8 encoding by Anonymous Monk
in thread create clone script for utf8 encoding by Aldebaran

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


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