Make spotlight index any file
Spotlight was not searching into certain files, even if simple text files (in my case .INI files)
mdimport -r /System/Library/Spotlight/RichText.mdimporterEnd of story.
mdimport -n -d1 file.extention
You should see one of the above, dependig if the type file is known by the OS or not
unknown UTI : Imported 'file.extention' of type 'dyn.ah62d4rv4ge80e2pcr74u'
Feed MyUTIs.bundle with this file extention.
Go to next bullet
known UTI : Imported 'file.extention' of type 'com.domain.other'
/System/Library/Spotlight/RichText.mdimporter/Contents/Info.plist (or other mdimporter if appropriate)mdimport -r /System/Library/Spotlight/RichText.mdimporter