CZO discussion
[here](https://chat.zulip.org/#narrow/stream/6-frontend/topic/code.20coverage/near/1487773).
This allows `zjquery_element.js` to have test utils that aren't always being used.
`upload.js` is mostly UI focused and has upcoming commits that are hard
to write unit tests for (and for which unit tests wouldn't make much sense).
This directory contains scripts that are used in building, managing,
testing, and other forms of work in a Zulip development environment.
Note that tools that are also useful in production belong in
scripts/ or should be Django management commands.