wpcrm_system_gdpr_delete_request_subject
The wpcrm_system_gdpr_delete_request_subject filter returns the subject line in the email that is sent with the GDPR delete request. GDPR requires that an individual can request to have their data deleted, and this email will provide you with notice of the request.
By default the subject line will be:
GDPR Delete Request
To change this, have the filter return a string with the desired text.