These Python files contain the full tree structures, functional group definitions, and trained values, described in the text, in a machine-readable syntax. You could  create your own classes to extract the data from the files, but they are currently compatible with the Reaction Mechanism Generator "RMG-Py"
https://github.com/ReactionMechanismGenerator/RMG-Py

The functional group definitions are given in RMG's "Adjacency List" syntax, which is described at 
http://reactionmechanismgenerator.github.io/RMG-Py/reference/molecule/adjlist.html
There is a tool to draw images from these adjacency lists at http://rmg.mit.edu
The "training" data contains all the specific reactions that were used to train the group values.