Sony published the short spec list of six new FF sensors. Those sensors are open for sale to third party camera makers. So it’s likely that you will see some future Pentax-Nikon-Panasonic cameras usin those sensors.
What’s particular is that the sensor named IMX521 uses the Quad Bayer Structure. Sony writes:
HDR function is available by dividing exposure time in the 4 same color pixels into long exposure pixels and short exposure pixels. or dividing conversion gain in the 4 same color pixels into LCG pixels and HCG pixels.
Quad Bayer RAW function makes it possible to readout 4 same color pixels without addition.
When normal operation. 4 same color pixels are added and made 1 pixel, and output as bayer pixel array. In addition, a group of divided 4 same color pixels is defined as 1 pixel unit in this product specification.
Here are the short sensor specs:
IMX311: 48,9MP (45° deg. square pix array)
IMX313: 48,9MP (16bit A/D, stacked 3:2, 30p at 16:9 FULL 8k readout. 60p at 6k with crop.)
IMX410: 24.6MP (24mpix, 19fps for photography. 6k 40fps, 4k crop 100fps.)
IMX521: 15MP with Quad Array