I'm using Mathematica 13.3.0.0.

I've downloaded the wl file to C:\Users\ianww\Documents\Mathematica\BernDirac.wl

I run:

ClearAll["Global`*"]
Get["C:\\Users\\ianww\\Documents\\Mathematica\\BernDirac.wl"]

I try (using esc ket esc to create the ket operator):

but I get a failed error:

$Failed

I also get the error if I comment out //MatrixForm:

$Failed

I get the same error if I try to run your example file.

I've also tried using Import rather than Get:

Import["C:\\Users\\ianww\\Documents\\Mathematica\\BernDirac.wl", "Rules"]

and it shows the file is loading ok because I get a comprehensive list of rules. However, the same $Failed error occurs.

Do you know if your wl is compatible with Mathematica 13.3.0.0? Or could there be some other cause that I've missed?