In Windows' "Virus and threat protection" settings there is the following checkbox (defaults to enabled): Automatic sample submission Send sample files

In Windows' "Virus and threat protection" settings there is the following checkbox (defaults to enabled): Automatic sample submission Send sample files to Microsoft to help protect you and others from potential threats. We'll prompt you if the file we need is likely to contain personal information. Regarding that last sentence, it is not documented what they consider "likely to contain personal information".