The phrase refers to the text within an email header that indicates a previous message contained an error and the current email serves to rectify that mistake. As an example, a sender might utilize such a header after realizing a key figure was inadvertently omitted from the original recipient list.
The use of a clear indicator of error rectification in an email is valuable for maintaining professional communication and credibility. It helps recipients quickly understand the context and purpose of the message, preventing confusion and potential misinterpretations of information. The practice stems from a need for efficient information management in a digital communication environment, ensuring that updated and accurate details are prioritized.