Yup, Marimo seems perfectly gittable and Deepnote looks more of the status quo.
> Human-readable format: The .deepnote YAML format replaces .ipynb's messy JSON with clean, version-control and human-friendly structure for projects and notebooks. You can organize multiple notebooks, integrations, and settings into a single .deepnote project for better structure and collaboration.
Marimo is much better for git than Jupyter. I only wish it had a gittable/reviewable version with output, too.
I confess that picking yaml doesn't feel safe to me. As much as it annoys people, fenced formats are the way, here. And if you aren't careful, you are going to recreate XML. Probably poorly.