Arduino IDE (development environment) *portable* install
An additional directory makes the Arduino IDE much more usable!
There are many advantages to installing the Arduino IDE in "portable mode". This logically separates the actual IDE from the personal settings, libraries and core architecture.
A normal Arduino IDE installation quickly overflows with additionally installed libraries, board definitions and other things. You can hardly find your way around in this chaos. A small trick ensures that the actual development environment and data for your own projects are cleanly separated from each other.