parallaxed.net

This article bears much credit to

http://devcha.blogspot.com/2007/01/edit-operating-system-version-check-in.html

Which took the most tricky of googlings to unearth…

Orca is a fantastic database editor for tinkering with the innards of MSI files. You can remove restrictions and all sorts of other voodoo.

The alteration relevant to my interests at the time (as mentioned in the article above) was “LaunchCondition”. Many thanks to the original article author.