See the 5 most recently modified posts:
git ls-files | xargs -I{} git log -1 --format="%aI {}" {} | sort -nr | head -n 5
See tags:
jq -r '.tags[]' .tags
Filter notes by tag:
jq -r '.notes[] | select(.tags[] == "concurrency") | .path' .tags
Find notes that do not have tags:
comm -23 <(ls *.py *.md *.ipynb | sort) <(jq -r '.notes[].path' .tags | sort)