When adding additional users to a file's extended ACLs, what is true about the default behaviour of the ACL mask for the file?

The file owner's permissions are not included in the calculation of the ACL mask; the mask only applies to the owning group, named users, and named groups.

The mask is not left unchanged by default; it is automatically updated to reflect the new set of permissions for affected entries.

While a restrictive mask could indirectly limit newly granted permissions, the default behavior is to recalculate the mask, not just print a warning when it's too restrictive.

By default, when `setfacl` is used to add new named user or group entries, the ACL mask is automatically adjusted to reflect the union of permissions granted to the file's owning group, all named users, and all named groups, ensuring it acts as an effective upper limit for these entries.