This is a new case of paperboard pizza slice wedges.

Some information from online:

About this item

• Recyclable and compostable.
• White interior and exterior
• Flat tray with fold-up sides for convenient storage
• Sturdy packaging made from premium paperboard (not fluted corrugated)
• Made in the USA from renewable resources
• Product Dimensions ‏ : ‎ 9.5 x 9 x 8.7 inches; 0.9 Ounces
• Item model number ‏ : ‎ 1480