As mentioned in other feedback, such as in "Track who joined what invite", knowing which invite is used can be a powerful tool for guild management. It allows for detecting the source(s) of influx of bad apples.
How would i implement this?
To enable tracking of inviters in a simple way, I would attach the user ID of the inviter to the Guild Member Add object. It is straight to the point and makes it easy to identify who invited the new user to the guild. the downside to this aproach is that it does not handle edge cases where some developers want to get more information about the invite used.
As alternative I would attach the invite object used to the Guild Member Add object. This would make it easy to read out the metadata for the invite and avoid a REST call to fetch the invite object. The downside to this aproach is that the event payload gets bloated with the less relevant information.
Bots can already provide this feature, why do we need this?
Although it is true that bots can theoretically track which invites get used, their approaches are fairly messy. They are required to internally monitor the state of the invite list and update it on each guild member added. This causes a lot of data to be sent over the wire that would barely see any use. Another downside is that in peak hours a bot might see multiple invites being used and would not able to determine which one has been used, an undesirable outcome.
Why do we need this feature sooner than later?
Discord is an evermore increasing platform for social use, with this increase in popularity and integration into the mainstream more and more bad actors have set their eyes on turning users of this platform into their victims. For example, in a guild I am in there have been multiple waves of scambots entering the guild and sending phishing links to the users. The guild had already increased the security measures to counter these bots, but they could still enter. By being able to find the account responsible for sending the invites used to harass the users the wave would've been able to be cut short and could be reported for TOS violations.