SWG (SWAG packet) is a specialized archive format associated with the SourceWare Archival Group (SWAG). SWAG is a historical collection of Pascal source code.
There are at least two different SWG formats, which we'll call "old" and "new".
New SWG format is based on generalized LHA format. It is approximately parsable as LHA, but the fields starting with the filename field seem to be repurposed, and it has a custom "compression scheme".
New format files have ASCII "
-sw1-" at offset 2.
At least some old format files start with "
-  → swag.zip - GDSOFT SWAG Packet Reader v3.13 (DOS software)
- Note that the Reader is also included in the allswags.zip file.
-  → swagwin.zip - SWAG for WINDOWS, v1.04
- SWAG.ZIP - Maybe the first version (DOS software)
- The HTML SWAG Home Page - The contents of SWAG are available here, but maybe not in SWG format.