I have a system for syncing item capability data that uses ICapabilityListener, as explained here:   I discovered in that thread that this pull request for 1.12.2 back in 2017 partially broke my system by changing Container#detectAndSendChanges to only call IContainerListener#sendSlotContents if a slot's Item, count or share tag has changed; which often won't be the case for capability-only updates.   The change does make sense for Vanilla IContainerListener implementations