The repository was noticed on 13 January by staff of the security firm UpGuard who notified AWS about the contents.
UpGuard said in a blog post that AWS had acted swiftly and secured access to the repository in a little more than two hours after being notified.
"The repository was structured as general storage rather than application code, with many files in the top level directory and no clear convention for the subdirectories," UpGuard said.
"Timestamps in the logs indicate they were generated throughout the second half of 2019."
There were many credentials in the repository, with many being access keys for various cloud services. Multiple AWS key pairs were also present, including one named rootkey.asc that suggested it would provide root access to the owner's account.
The repository also contained numerous documents that enabled the UpGuard staff to establish who owned it.
"A LinkedIn profile matching the exact full name identified one person who listed AWS as their employer in a role that matched the kinds of data found in the repository," the company wrote.
"Other documents in the repository included training for AWS personnel and documents marked as 'Amazon Confidential'. Based on this evidence, UpGuard is confident the data originated from an AWS engineer."