The Panda version of TOPS-20 includes a vast set of extensions and bugfixes, some of which originated at Stanford in the 1970s and 1980s, as well as a substantial library of non-DEC software available nowhere else. 
The Panda distribution is the creation of Mark Crispin (MRC). May he rest in peace.
The code in this repository was extracted from the 16-Jun-2006 snapshot of the Panda distribution of TOPS-20.