RMAN Backup - Additional Backup Being Create

Hi,
For development, I have started to use RMAN to take backups of an XE database I have.

When I back the database up using RMAN, it is adding an additional item onto my backups. In the images below, you can see that my intended backups are all tagged as XE but this additional backup also appears each time. Can someone explain to me what this is for please? I am backing up the database (the extra item appears in full or incremental level 0 mode), the archive logs and the control file.

Thanks.

Attachment 672 Attachment 673 Attachment 674