Files with sqd file extension can also be found as saved messages from the Squish program for FidoNet.
There is one other file type using
the SQD file extension!
.sqd - Sysquake session data file
SQD file extension - Squish message base file format
What is sqd file? How to open sqd files?
File type specification:
The sqd file extension is also related to Squish program and used for its default message format.
Squish is both the name of a FidoNet mail tossing application originally designed for DOS and OS/2, and the name of the primary mail storage format in which this application stores.
Most likely old and no longer used format.
This sqd 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.