Complex sentence: Started as an OpenOffice.org port to Macs using the Aqua, instead of X11 windowing server, which, in theory, should make it more stable than the X11 port of other suites.
Split into simpler sentences: Started as an OpenOffice.org port to Macs using the Aqua instead of X11 windowing server. In theory that should make it more stable than the X11 port of other suites.