Seems to be from 2017? There aren't any comments in the thread.
OP can you expand on why you found this interesting?
The post says:
ACME is designed to be extensible by adding new JSON fields, which should be ignored by clients that do not understand them. Unfortunately, some of the earliest ACME clients were intolerant of new fields, which has made it hard to introduce new fields ... we have decided to add a key/keys to directory with randomly generated names in order to dissuade client developers from writing clients in such a way that prevents us from adding new keys in the future.
OP can you expand on why you found this interesting?
The post says:
ACME is designed to be extensible by adding new JSON fields, which should be ignored by clients that do not understand them. Unfortunately, some of the earliest ACME clients were intolerant of new fields, which has made it hard to introduce new fields ... we have decided to add a key/keys to directory with randomly generated names in order to dissuade client developers from writing clients in such a way that prevents us from adding new keys in the future.