Sphinx might output references to memory addresses and generate a json index file with entries in random order or with non-deterministic values (eg. searchindex.js). See https://bugs.debian.org/822197 for memory address issue . searchindex.js needs sort_keys=True (jsonimpl.py) but the key values vary too.
The python-changelog library generates references in a nondeterministic order.
Our notes about issues affecting packages are stored in notes.git and are targeted at packages in Debian in 'unstable/amd64' (unless they say otherwise).