These file types conform to the Common File Structure format.
The File Payload of these files contain a certificate signing request in PEM format. To generate a CSR see 0xEF03 - Generate CSR (WLAN Only).
The device will erase the CSR file from volatile memory after the host fetches it with 0xD821 - Start Get File from Device. After fetching the CSR, the keys used to generate the CSR will still exist in non-volatile memory associated with a CSR and can be used to generate a new CSR if needed.