Utf8 extension is associated with Unicode UTF8 text file. You can try to open Utf8 files with Note Pad.
It is a text file which uses UTF8 format. It can be easily opened by many text softwares. For example, you can try to open utf8 files with Note Pad. In this case you should give the File-Save command. Then select utf-8 from the coding section of the window.
UTF-8 (8-bit Unicode Transformation Format)
What to use UTF8
which page related to UTF8 file
UTF8 Related Searches
You can check related links about UTF8 fileextension.