MGT was an early SGF program. The MGT program was originally developed to be a companion for the series, "From My Go Teacher" which is a collection of problems and study material that can still be found on the net.
It used ASCII graphics for displaying the board not much unlike the syntax SL is using today.
- WinMGT, an SGF program for Windows. Actually it is only sharing the same name, but not the developers or any code with the original MGT program.
- MGT at Debian: http://packages.debian.org/stable/mgt
- MGT reference manual (for the unix version): http://olympus.het.brown.edu/cgi-bin/man2html?mgt+6, a tool to view and edit MGT files