The rarity of the letter 'e' is a sign that the #codemakers knew their stuff.
Because 'e' is the most common letter (in old as in modern French), it is what #codeBreakers would be looking for first.
And the fake symbols were simply put in to sow more confusion.
While most symbols represented letters or combinations of letters, others represented whole words - like a needle for English King Henry VIII.
#Codes
#Ciphers
https://www.bbc.com/news/world-europe-63757443