Jameel Square (which achieved the first LEED Gold certification for a commercial building in Saudi Arabia) and the KAPSARC Headquarters (which achieved LEED Platinum status). The term "Office Downtown" does not seem to refer to a specific, known LEED Platinum-certified property.
 

Prominent LEED-certified buildings in Saudi Arabia:

• Jameel Square:

  This is Saudi Arabia's first commercial building to receive LEED Gold certification, according to a report from نبض الحدث. 

• King Abdullah Petroleum Studies and Research Center (KAPSARC) Headquarters:

  This educational building in Riyadh achieved LEED Platinum status in 2017, according to USSBC. 

Why the confusion?

• The LEED certification system is managed by the U.S. Green Building Council (USGBC). 
• LEED Platinum is the highest level of this certification, signifying adherence to the most stringent sustainability standards. 
• Saudi Arabia also has its own national green building rating system, Mostadam, which is developed by the Ministry of Municipal and Rural Affairs and Housing and administered by Sustainable Building.