I think it is created in the directory where the .ccf is, which doesn't need to be the same as the directory where decodeccf.exe is.

Also it is a .txt file. The contents are tab delimited values, which are accepted by most programs (including Excel) when they are expecting CSV (comma delimited values).

But unlike .csv or xls files, the .txt file won't open automatically in Excel when you double click it. The most reliable way to open the .txt file is to launch Excel first, then use its file open dialog to find and open the .txt file (be sure to tell it to look for .txt of for all files while browsing).