From the IR docs: IR originally stood for "Init
Restarter" and was written to get the GSBug Init installed after booting
because it didn't work with my terminal program.  It was quickly expanded
to also load CDAs, NDAs and GS/OS Drivers, and made it onto the Developer
CD.  There it stood for a long time.

The new features in System Software 6.0, specifically inter-process
communication (IPC), make it possible to go IR 1.0 one better -- IR 2.0.2
installs a Finder Extension so that CDAs, NDAs, inits and GS/OS drivers
and even Finder Extensions are installed without ever leaving the Finder.
It has preferences, presented through an "Extras" menu item and does a lot
more than 1.0.