In response to the many classified intelligence leaks in 2013 and the resulting demands by Silicon Valley companies to bring more transparency into the surveillance process, Google has been allowed by the FBI to publish the identities of several email accounts that were sought. Previously, several companies held that any user data should not be accessible for private warrants without court approval, mainly because the FBI can issue letters without previous judicial oversight.

Now, Google has published a total of eight letters from March 2010 to September 2015 that requested information on 21 user accounts. The information is provided under the company’s “transparency report,” which usually only shares the number of requests it receives from government agencies over six month periods. While the email addresses have been omitted, all but one of them are listed as belonging to the gmail.com domain. This could indicate that one address was a non-Gmail account hosted on the company’s services.

The FBI letters note that the agency is not requesting the subject line or content of the emails, but simply that Google is obligated (by 18 US Code 2709) to provide the name, address, length of service and email transaction histories belong with each account. However, the agency then provides a gagging order that the company is not allowed to disclose any information in the letters or disclose the fact that the FBI had even sought or obtained access to the information.

According to the 2015 USA Freedom Act passed last summer, Google and other companies are legally allowed to disclose some of the national security letters. The FBI did request to omit the name of the officer making the request, and the company complied.