MLD files refer to the multi-language dictionary files used by the AMLANGCONV command.
The path to the folder containing MLD files is in the system editor keys PowerPack
Paths
MldPath and Acad/M
Paths
MldPath(Configuration file settings
gef@Paths@MldPath and
gen@Paths@MldPath).
By default, the key points to C:\ProgramData\Autodesk\AutoCAD Mechanical 2027\Acadm\TRANSLATOR.