This is a part of the transformation scene that depicts Buddha giving a sermon of the “Inconceivable Dharmas of the Buddhas” chapter.
Vairocana Buddha is at the center, surrounded by various bodhisattvas, On the left is written “Blue Lotus Bodhisattva’s Sermon.” As the sutra explains, the Buddha had the Blue Lotus Bodhisattva give a sermon on the inconceivable dharmas to the assembled bodhisattvas.
The mudra made by the Buddha at the center is called the vajra mudrā in Sanskrit or wisdom-fist mudra in English. Both hands are raised up in front of the chest and the fingers of the right hand are wrapped around and cover the left index finger.
This mudra is typically associated with Vairocana.