Constant MAX_JSON_DEPTH 

pub const MAX_JSON_DEPTH: usize = 64;

Bracket nesting accepted in a response. The ResourceManager’s deepest answer, the CapacityScheduler’s queue tree, measured 16 levels against Hadoop 3.5.0 with one level of queues; each level below adds three (queues, queue, the entry), so 64 leaves room for a queue hierarchy fifteen deep.