status - Margin and battery status → Does this message originate from the gateway or the device? Is every gateway/device capable of emitting these messages with batteryLevel info? what is margin here?
ack - Confirmed downlink (n)ack → Is this AckEvent a result of sending a downlink message with confirmed: true ?
txack - Downlink transmission ack → Is this TxAckEvent only for downlink messages indicating that the downlink message is sent away from the LNS? What is the txInfo section saying in the message?
location - Location event → Is this a location sent from the device? Are all devices able to send this type of location?
integration - Integration event → What could a IntegrationEvent message be used for?
These are related to various events that occur in a LoRaWAN network.
Status: this is related to the DevStatusReq/DevStatusAns MAC commands. Compliant devices will implement it and it may be used to indicate the battery level/status and signal strength of last downlink received by the device. Margin refers to the signal strength above the demodulation floor (which is defined by the type of chip used, typically a SX1276). The DevStatusAns is sent in response to the LNS sending DevStatusReq, for which Chirpstack can be made to send.
Ack: yes, this even indicates the outcome of confirmed downlinks.
TxAck: indicates whenever the gateway confirmed transmission of a downlink message. TxInfo indicates the characteristics of the transmission, such as the centre frequency.
Location: this is not sent by the device. But Chirpstack can determine its location. How, I am not sure, as I have not studied this feature in detail.
Integration: I have no idea, sorry. But it is not necessary for my usage of Chirpstack.
This is currently only used for the LoRa Cloud integration. It can work with the Semtech modem firmware to handle fragmented payloads (thus a large payload fragmented over multiple uplinks). In such case an integration event could be a defragmented payload.