sys.xp_delete_files and ‘allow filesystem enumeration’: two new undocumented items in SQL Server 2019

sys.xp_delete_files and 'allow filesystem enumeration': two new undocumented items in SQL Server 2019

Actual Difference Between EXISTS(SELECT 1 …), EXISTS(SELECT * …), and EXISTS(SELECT column …)

Is EXISTS(SELECT 1 ...) better than EXISTS(SELECT * ...)? Who would know better than SQL Server?