For those interested in playing with or doing research using model internals, the TransformerLens [1] project appears to be the leading open-source tooling in this area. It allows for loading dozens of different models, adding hooks, displaying activations in a format compatible with CircuitsVis, and other (mechanistic) interpretability work.<p>[1] <a href="https://github.com/neelnanda-io/TransformerLens">https://github.com/neelnanda-io/TransformerLens</a><p>[2] <a href="https://github.com/alan-cooney/CircuitsVis">https://github.com/alan-cooney/CircuitsVis</a>