I was poking around in the registry and I noticed that a lot of the file extension folders in HKEY_LOCAL_MACHINE contain a folder labeled "PersistentHandler". What is PersistentHandler? I tried looking it up on search engines, but I couldn't find too much out. I also noticed that file extensions that used the same default program had identical value data in the registry files inside their PersistentHandler folder. Is this just the address of the default program for the file extension?
PersistentHandlers are small programs used by the Windows search feature when searching for text inside files. Many files, such a Word files, contain a mixture of plain text and binary information. These handlers allow the search feature to ignore the non-plain text portions of registered file types.