This page provides information on Telemetry for the V-Ray for Nuke Improvement Program.
For Windows, the files can be found in the folder C:\Users\<username>\AppData\Local\ChaosGroup\telemetry.
For Linux, the files can be found in the home directory of the current user: ${HOME}/.ChaosGroup/telemetry/. The collected data is viewable with a text editor.
The Feedback program is activated by enabling Help make V-Ray even better checkbox, available upon pressing the Advanced button of the installer.
The Feedback program settings can be changed at any time in Nuke after installing V-Ray. They can be accessed through the VRayRenderer node > Global tab > Misc rollout > Feedback program settings...