How to update TimerTC3.cpp


I am new to this forum and joined because I just bought my first Seeeduino XIAO.
Up to now I used PICs from MicroChip.

I use the TimerTC3.h by just adding it in my sketch (#include <TimerTC3.h>).
I notice the same bug that was reported (and solved) more than a year ago by @Katsux.
(Timer interrupts on XIAO - #9 by katsux)
There the bug is fixed by modifying a line in TimerTC3.cpp
My problem at this time is: how can I get this update to appear in my arduino.ide?
I guess it must be simple, but I cannot find TimerTC3.cpp anywhere using Arduino.IDE…

TimerTC3.cpp can be found here.

Now suddenly everything works! Thank you, msfujino!
My problem appeared to be more basic than Seeeduino: Windows basics.
As I was not viewing “hidden files”, my searches did not
find anything.
I found it and replaced it with the suggested update by katsux. So I thank you both.
Do you think the issue will go away for future Seeeduino buyers automatically, i.e. will the inclusion of take care of this issue?