No documentation about EXPLAIN fields in JSON fornat

[Matias Fernandez]

Hi, I'm trying to learn how to take advantage of EXPLAIN FORMAT=JSON output but I couldn't find any documentation inside mysql docs about the meaning of different fields like:

rows_examined_per_scan
rows_produced_per_join
filtered
read_cost
eval_cost
prefix_cost
Etc...

Is there any place where I can find an explanation on that? Is there any plan to add that to the docs?

Thanks!