why was dev taken private?

This MIT codebase is no longer maintained but the published package at npmjs.com is and is also MIT. The catch is that https://github.com/mapbox/node-or-tools-internal is not a public repo.

Why did Mapbox take this private? Is a public future on the horizon?

The issue names no source file, test, or entry point and asks why the development repository was made private. Start by reviewing the repository and published npm package links in the issue. Done means a maintainer explains the repository status and whether a public future is planned.

Written by the indexing model from the issue text.