On windows, the file can be found in: C:\Users\<your user name>\AppData\LocalLow\Tin Can Studio\Tin Can\ and is called Keys.Json

AppData is a hidden folder by default, so you may need to enable viewing for hidden folders. Alternatively, if you paste C:\Users\<your user name>\AppData\ in the address bar in explorer and hit enter, it should take you there regardless of your visibility settings.

The format of the file is fairly self-explanatory with each key associated with a name and key value. The numeric value of the key is what actually sets the keybinding. These values are the ASCII value for the key of interest.

If you are not familiar with ASCII, a nice lookup table can be found here.
https://www.ascii-code.com

For the key you want to bind, look it up in the "Symbol" column and then use the number for that key under the corresponding "Dec" column.

WARNING: The case of the letter matters, so if you want to rebind a key to "f" use lowercase f (=102) not uppercase F (=70).

For example, say I want to rebind interact to "e" instead of "f"

I would change this:

To this:

This is because interact by default is f (ascii 101) and I am changing it to e (ascii 102).