With as many as 500 or more appexes in your Mac, these have become widely used and important. What they are, where they are, and how to control them.
appex
How to discover which QuickLook generator or app extension should be creating Thumbnails or Previews for different file types, using this new version of Mints.
Have documents saved by your favourite apps lost their custom Thumbnails and Previews in Sequoia? Here’s what has gone wrong, and what you do about it.
The Eclectic Light Company 