A slightly revised version (v. 1.41) of the MLA Best Practices for Using LCMPT (March 31, 2020) is now available, and should be used in place of the previous version.  The main change is the deletion in its entirety of footnote 10 in version 1.4. Deleted:  As of this writing, 382 subfields $e, $r and $t are defined in the MARC Authorities Format, but are not yet approved for use in LC/NACO authority records; see the Descriptive Cataloging Manual, Section Z1 for more information (via Cataloger’s Desktop or https://www.loc.gov/catdir/cpso/dcmz1.pdf). Aside from that restriction and the second indicator difference mentioned above, these best practices guidelines apply equally to 382 fields in bibliographic and authority records. This brings the document in line with the change by LC, announced in March ahead of the April, 2020 update to DCM Z1, that subfields in the 382 field (Medium of Performance) are available for use in authority records (by NACO-Music