The config settings are passed via /props. Use the browser developer tools network tab and you should see them passed through there.

I see Olmo by AllenAI frequently used in research. The publish all the checkpoints of training and all training sources. https://allenai.org/olmo / https://huggingface.co/collections/allenai/olmo-3

Here’s the link to the dataset used to train Olmo 3: https://huggingface.co/datasets/allenai/dolma3_mix-6T

It’s fairly modern. Olmo 3.1 was released January 2026.

Yes, Opus/Fable 5. If you have the opportunity, play around with it. It writes in a format that tries so hard to be concise (while blurting out a monumental essay) that you can hardly understand it, and repeats the same phrases all the time.