Are you referring to the AD object RDN change to \0ADEL:<ObjectGUID>?
\0A is null terminator character.
ObjectGUID is added because DeletedObject is single container( you can imagine like single OU). If I delete two object with same RDN but located in different OUs, once both will move to single OU and cause conflict. To maintain the uniqueness of RDN, original ObjectGUID is added.
For example, we have two Objects
Above objects have same RDN but in different LDAP path so, can co-exits. But when I delete both the objects, both will move to single container, DeletedObjects and than there will be no unqiueness in the LDAP path
To avoid this conflict, Object GUIDs are added