No documentation on mem3 options in CouchDB

[Bolebo]

Description

I'm trying to solve a problem of "pending_changes" between the nodes of my cluster (6 nodes with 3 replicas of each shard).
I'm suspecting that mem3 configuration is involved but I can't find any description on the CouchDB documentation but the default.ini config file suggests it is possible:
;[mem3]
;nodes_db = _nodes
;shard_cache_size = 25000
;shards_db = _dbs
;sync_concurrency = 10

Is it possible to have a description and the default value of those config items?

And maybe some tips to manage the "pending_changes" when replicating a large amount of docs between nodes :)

Thank you in advance.

Regards,
Boris

Steps to Reproduce

Expected Behaviour

Your Environment

• CouchDB version used: 3.3.2
• Browser name and version: --
• Operating system and version: Ubuntu 22.04

Additional Context