.xml, .sql, .bat
.log (mIRC and Trillian)
.cs, .vb (Visual Studio .NET source code files)
.frm, .bas, .cls (Visual Basic 6 source code files)
.wpd (WordPerfect), .rtf (Rich Text File)

Additionally, adding non-ASCII file extensions such as .wav, .rar, .png, .psd etc. will index just the filenames for search (PDF content is still not searchable, however). You can also remove support for any of the extensions that Google included and you do not want indexed.

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