Because there are words \"Designed by Apple in California. Assembled in China.\" on the internal cover of the AirPods Pro charging bin, it can be proved that there are words inside the charging bin. In addition, there are battery indicators inside the charging compartment, which are used to show the power status of the charging compartment and headphones, which is also a more important design feature of AirPods Pro.
So, the AirPods Pro does have words inside the charging compartment.