https://www.cnet.com/roadshow/news/ford-explorer-generations-history-1991/

The first Explorer was built off the Ford Ranger's pickup truck chassis and shared a plethora of parts with its more utilitarian sibling, namely body panels ahead of the A-pillar and a dashboard. Although the Explorer resembled the (also Ranger-based) two-door Ford Bronco II compact SUV of the 1989 and 1990 model years, the Explorer was actually a full segment size larger.

The two-door Explorer Sport was 12.6 inches longer and 2.2 inches wider than the Bronco II, while the four-door Explorer boasted an additional 22.4 inches of length. It was also more aerodynamic and modern looking, thanks to flush side glass, integrated mirrors and the lack of drip rails, which were still used on the Ranger of that period. The Explorer also came in a well-known, two-tone Eddie Bauer trim -- a tie-in with the outdoorsy clothing store. The Eddie Bauer Explorer was enough of a hit that it returned for subsequent generations.