MacWorks Plus was a complete implementation (port) of the Macintosh Plus 128K ROM on the Apple Lisa and Macintosh XL computer systems,  a contract developer named Chuck Lukaszewski, who was responsible for versions up through 1.1(h), which supported up to which graphical user interface-based operating system for Macintosh computers, and was shipped with various Macintosh computers until it was succeeded by System 7 in 1991?
MacWorks Plus:  It was developed for Sun Remarketing of Cache Valley, Utah, under license from Apple Inc., by a contract developer named Chuck Lukaszewski, who was responsible for versions up through 1.1(h), which supported up to Macintosh System 6.0.3. System 6: System 6 (also referred to as System Software 6) is a graphical user interface-based operating system for Macintosh computers.
System 6