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I see this character in Firebug 
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I don't know why this is happening, there's no such character in my code. For Firefox it's OK, but in IE everything breaks. I can't even search for this character in Google.
I saved my file with utf-8 encoding without bom.
An old stupid trick that works in this case... paste code from your editor to ms notepad, then viceversa, and evil character will disappears ! I take inspiration from wyisyg/msword copypaste problem. Notepad++ utf-8 w/out BOM works as well.
If you are using Notepad++, "Menu" >> "Encoding" >> "Convert to UTF-8" your "include" files.
Just use notepad ++ with encoding UTF-8 without BOM.
"I don't know why this is happening"
Well I have just run into a possible cause:-) Your HTML page is being assembled from separate files. Perhaps you have files which only contain the body or banner portion of your final page. Those files contain a BOM (0xFEFF) marker. Then as part of the merge process you are running HTML tidy or xmllint over the final merged HTML file.
That will cause it!