Files with ppm_d file extension is related to the Nokia post programmable memory file format.
PPM_D file extension - Nokia post programmable memory data
What is ppm_d file? How to open ppm_d files?
File type specification:
The ppm_d file extension is associated with the post programmable memory file format, a file format used to store some parts (often language packs) of firmware for Nokia phones. These files can be "flashed" to phone.
This ppm_d file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.