In video, common frame rates are 30, 29.97, 24, and 23.976. (Almost) anything else will be a multiple of those. Your monitor might not actually run at 30hz * 4, it runs at 29.97hz * 4 which is why you see an option like 119.88. Sometimes that’s displayed as 120 to the user for simplicity, but in this case they’re showing the actual value (or it might support both).
Ya got some quite not rounded numbers there ...
In video, common frame rates are 30, 29.97, 24, and 23.976. (Almost) anything else will be a multiple of those. Your monitor might not actually run at 30hz * 4, it runs at 29.97hz * 4 which is why you see an option like 119.88. Sometimes that’s displayed as 120 to the user for simplicity, but in this case they’re showing the actual value (or it might support both).
Where do the weird fractions come from?
https://piped.video/watch?v=3GJUM6pCpew
Windows hides the actual refresh rate to make it look better. Linux shows you what it actually is.
I think it's because of HDMI the values aren't whole.
DisplayPort would display whole numbers
I don't think that's it, rather the monitors supported refresh rates. (Think!=know)