Not sure if it's appropriate but here's my own take at a very terse restatement of Shannon's original paper [1]:
https://mechaelephant.com/dev/Shannon-Entropy/
I recommend everyone that's interested to read Shannon's original paper. It's one of the few examples of an original paper that's both clear and readable.
[1] https://homes.cs.washington.edu/~ewein/blog/2020/07/14/entro...