Yes, it’s true. Gmail announced last Thursday at M3AAWG that they were piloting a new Feedback loop.
The Gmail FBL is currently for ESPs only. The announcement during MAAWG was that only MAAWG ESP members were eligible. They are requiring a DKIM signature for the FBL, but ESPs using individual customer d= values can get a FBL based on IPs. They are also not providing ANY information that reveals the complainer. Gmail’s intention is only to give ESPs feedback so that ESPs can prevent abuse. They are not giving feedback so complainers can be removed.
The email has a .csv attachment that has 3 columns: date, identifier and complaint rate.
The identifier is an ESP provided customer identifier. One of the ESPs I talked to said they were adding an X-header into their emails.
I’ve heard from beta testers that there is a minimum of 100 complaints before you’ll get any report.
Reports are sent daily if there is sufficient traffic to trigger them.
If you’re a MAAWG member, check the senders list for the signup URL.