Google lens tells me it's the airport layout plan at the CLT airport website
https://www.cltairport.com/airport-info/
scroll to the bottom, click on AIRPORT LAYOUT PLAN

detailed notes show there are 2 phases, for buidings, darker red is phase 1, lighter red is phase 2
The expansion of the terminal that will include the new Admirals Club is thankfully Phase 1, but I don't know the timeline for either phase actually happening.
The area I'm referring to is the rectangular shape shown just "above" the distinctive round rotunda area of the C/D club.
In actuality, the diagram was rotated 90 degrees from true directions....The expanded retail area that will go next to the rotunda is actually EAST of the rotunda.
The new club will be one level up from that in the new construction, in an area much larger than "Just" the red area. there will be an entire new floor upstairs that is added.
the red is just the new footprint