An SPDX-License-Identifier declares an expression. SPDX-FileCopyrightText records the holder and publication information. Neither tag replaces the need for the applicable license text or permits you to name a holder who did not contribute.
REUSE 3.3 supports file headers, adjacent .license files and REUSE.toml annotations. Sidecars help for formats that cannot carry comments. Annotation precedence matters when declarations overlap.
The drill focuses on the header and sidecar subset. Declare the actual MIT grant and the supplied copyright holder, then keep the associated license text with the release. A syntactically valid but false GPL header is not a correct repair.
Attribution etiquette includes retaining useful provenance even when a specific artifact has no additional legal attribution condition. Keep that practice distinct from the license obligations the engine grades.