What does Synology 'Secure Erase' actually do?

On my DS1812+ with a ST8000NE001, this is what Synology’s “Secure Erase” actually does in the background. The following example is for secure erasing /dev/sde:

• It renames /dev/sde to /dev/erasesde, probably to avoid confusion or using it in any other way.
• It uses hdparm to issue a secure erase command to the drive:

/usr/bin/hdparm --user-master u --security-erase synology /dev/erasesde

Notably, it uses the secure erase password synology. So if the process is interrrupted in any way, you might need to unlock your partially secure-erased drive with the password synology.

Also note that Synology does not use enhanced secure erase. See this StackExchange post for a detailed explanation. However, for many modern-ish drives, both methods likely do the same.