Recently, python-docutils was updated in Debian unstable (from version 0.21.2 to 0.22.2), which resulted in this bug being filed in the Debian BTS (severity: serious).
kevin.albertson@mongodb.com was able to reproduce/confirm with uv:
# Build with docutils==0.21.2 (from uv.lock) ... OK uv run --frozen sphinx-build -WEn -bhtml src/libmongoc/doc/ src/libmongoc/doc/html # Build with docutils==0.22.2 ... error uv run --frozen --with="docutils==0.22.2" sphinx-build -WEn -bhtml src/libmongoc/doc/ src/libmongoc/doc/html