Question for px4fmu-v4 and px4fmu-v4pro

I found both px4fmu-v4 and px4fmu-v4pro on source code.

Do they work on pixracer?

I guess their difference is clock speed (168Mhz vs 180Mhz and so on)
But, I just want to make sure before code analysis.

Thank you

Its for different boards and no, they will not work on the same board. px4fmu-v4_default is for Pixracer, the other for Pixhawk 3 Pro.

I guess there is no official board for pixhawk3. Is that true?
Also, I am wondering whether pixhawk3 has (or will have) fail co-processor and WiFi.