Short answers, pulled from the story.
Populous Holdings, Inc. is a global architectural firm specializing in sports stadiums, training centres, entertainment arenas, convention centers, and aviation and esports facilities. It has designed more than 3,500 projects worth over sixty billion dollars worldwide, with notable work including Yankee Stadium, the 2012 London Olympic Stadium, and the Sphere in Las Vegas.
Populous became independently owned and operated in January 2009, following a management buyout from HOK Group. It had previously operated as HOK Sport Venue Event, a sports design group founded within HOK in 1983.
Oriole Park at Camden Yards in Baltimore launched the retro era of baseball park design in the 1990s. Populous incorporated the red brick facade of the Baltimore and Ohio Warehouse into the design, setting a template of embedding local history and "classic ballpark" aesthetics into new construction.
From 1992 to 2012, HOK Sport and Populous served as lead architects on 14 Major League Baseball stadiums and helped renovate four existing ones.
Populous has a major design presence in Saudi Arabia. Eleven of the 14 stadiums included in the Saudi 2034 World Cup bid are either designed or being redeveloped by the firm.
Jerry Sincoff created the sports group within HOK in 1983, initially called the Sports Facilities Group. The studio was led by architect Ron Labinski, who has been described as "the world's first sports venue architect." The group started with eight architects in Kansas City and grew to 185 people by 1996.