On Monday, June 15, 2015 Mozilla announced on the Add-ons blog a free special edition t-shirt for eligible AMO developers. Eligible developers were requested to sign up via Google Form and asked to input their full name, full address, telephone number and T-shirt size.

This document was mistakenly configured to allow potential public access for less than 24 hours, exposing the response data for 70 developers. As soon as the incident was discovered, we immediately changed the permission level to private access. Other than the developer who discovered and reported this incident, we are not aware of anyone without authorization accessing the spreadsheet.

We have notified the affected individuals. We regret any inconvenience or concern this incident may have caused our AMO developer community.

https://blog.mozilla.org/addons/2015/07/02/t-shirt-form-data-exposure/