So, "help" in the console does show that there is a "fov" option:
But using it in the console for a larger value doesn't do anything. You can make the fov smaller, such as "fov 60" and you can make it bigger up to the slider's max of 85: "fov 85". if you try a value larger than 85, it sets the ceiling at 85.
Maybe the developers locked the max to 85.0f. Maybe there is a way to adjust the fov via a mod?