Following is link to LIN Transceiver Datasheet:

https://www.infineon.com/dgdl/Infineon-TLE7258-DS-...

Page 11 has the following statement:

" The BUS output is terminated to Vs via the internal termination resistor RBUS. "

Does this mean that BUS output voltage is Vs ?

Yes, in the recessive state. see block digram on page 4, figure 1. read the lin bus specification.