What's the bXCAN RXD recessive signal on STM32L476?

[ANguy.1]

I'm reading RM0351 for STM32L476, "To be synchronized the hardware has to monitor a sequence of 11 consecutive recessive bits on the CAN RX signal." Is RX recessive bit a digital high or low signal? I couldn't find the info on the datasheet which only says "Refer to Section 6.3.14: I/O port characteristics for more details on the input/output alternate

function characteristics (CAN_TX and CAN_RX)."

[Tesla DeLorean]

The STM32 CAN design monitors the bus state via CAN_RX to see it matches what it drives from CAN_TX, the signal on the bus can be dominated by a "LOW" signal from another bus users, ie as the ID bits clock out from two contending devices the guy driving low wins the arbitration, and guy with the high backs off, until only one device remains active.

The Regressive bit is HIGH, the Dominant bit is LOW

https://e2e.ti.com/blogs_/b/industrial_strength/archive/2015/06/04/what-do-can-bus-signals-look-like