MP-3 Media marking
What the standard requires
a. Mark system media indicating the distribution limitations, handling caveats, and applicable security markings (if any) of the information; and b. Exempt [types of media exempted from marking] from marking if the media remain within [controlled areas].
Quoted verbatim from NIST SP 800-53 Rev 5 (OSCAL catalog), which is in the public domain.
Cross-framework mappings
No cross-framework mapping is seeded for this control. That is stated rather than filled in: a mapping nobody authored is worse than a gap you can see.
Track MP-3 with evidence behind it
In CMDash this control is a row with an owner, a status, uploaded evidence kept with its full history, and an export an assessor can read.