What kind of mangling has the LDC2 -X JsonFile "deco" field?

[realhet]

Hello,

I'm trying to get information from the JsonFile produced by LDC2, 
but having no clue how to decode this:

For example:
header: KeywordCat kwCatOf(int k)
   "deco" : "FAyaZE3het8keywords10KeywordCat",

The "deco" field contains the full name of the return type 
het.keywords.KeywordCat, but in front of that I don't know how to 
decode that "FAyaZE".

Also this is how a string return type is encoded: "FiZAya"

I tried std.demangle and and online GCC demangler, but no luck.

Anyone can help me telling how to decode these please?

Thank you in advance!