.ICALTODO File Extension
File TypeiCal To Do File
What is an ICALTODO file?
Calendar data file used by Spotlight, a search utility included with Mac OS X; contains cached todo data used for searches; saved to the [user]/Library/Caches/Metadata/iCal/ directory.
ICALTODO files correspond to calendar todo items created by the user in iCal.
NOTE: Apple Calendar was formerly known as Apple iCal but was changed in 2012 with the release of OS X Mountain Lion.