If you use the installer to install the Arduino IDE, then you are asked where you want to install it. If you using the .ZIP file version of the IDE, then it's wherever you unzipped the file at. If you use the Microsoft App store version of the Arduino IDE, then it is a bit better hidden away, but the location is not really that useful to know because apps are locked down pretty tight with security restrictions so you would have to go through a lot of hassle to be able to modify any files in that path.
But none of that is even relevant if you're using Arduino IDE 2.0.0-beta now because it doesn't come with a bundled installation of Arduino AVR boards, so you won't find the file you're looking for at that path. And in fact, even using Arduino IDE 1.8.15, although you will find the file there, that isn't necessarily the copy of the file that is being used by the Arduino IDE, since another copy might have been installed to another location.
I'm going to provide you with the instructions for finding the path of the active copy of this file. Just do this:
Start the Arduino IDE.
Select File > Preferences from the Arduino IDE's menus.
Check the box next to "Show verbose output during:  compilation".
Click the OK button.
Select File > New from the Arduino IDE's menus.
Add the following code to the top of the sketch:
Select the Arduino board you are planning to use for your switch controller from the Arduino IDE's Tools > Board menu. If the platform for your board isn't shown there, then you will need to use Boards Manager to install it.
Select Sketch > Verify/Compile from the Arduino IDE's menus.
Wait for the compilation to end.
Examine the contents of the black console pane at the bottom of the Arduino IDE window. There you will find something like this:
Using library HID at version 1.0 in folder: C:\Users\per\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.3\libraries\HID
That is the location of the file you are searching for.
Note that the C:\Users\<user name>\AppData folder is hidden in Windows File Manager by default. You will need to adjust the settings in order to make it show hidden folders.