To download the discovered certificate in PEM or VFX format, you typically need to use the sys_certificate table, which contains attachments for certificates. If the certificates are not in the desired format, you may need to perform some customization, as out-of-the-box (OOTB) functionality in ServiceNow may not directly support exporting in these specific formats. Custom scripts or tools could be used to convert the certificate data from the system into PEM or VFX format. The sn_disco_certmgmt_cmdb_installed_certificate table is more related to discovery data but may not offer the download in the exact format you need. Customization is likely required unless a new feature or plugin has been introduced in the platform to support this.