When you build one thing, you quietly touch others. A new page needs a library, so the manifest changes. A new capability needs explaining, so the guide changes. None of it is the feature. All of it ships in the feature's company.
Here are the most-companioned files on the site, each star sized by how many distinct areas it changed alongside. They are the constellation a thousand commits trace without meaning to.
the brightest starThe manifest that everything needs
The most-companioned file on the site is package.json, changed alongside 31 of the 71 areas — and its shadow, package-lock.json, close behind at 13. Nearly every feature, to do its one new thing, first asks for a tool it doesn't yet have. The manifest is where that asking is recorded. It is the most boring file in the repository and the most universally disturbed, because dependency is the most common form of reaching sideways.
the meaningful oneThe file that ships with the telling
But look at the second star. CLAUDE.md — the workhorse of essay No. 05, the guide no visitor loads — is a companion to 18 separate areas. It imports into nothing; no module depends on it. It travels with everything for a different reason: because a feature is not finished when it works, only when it is written down. The manifest rides along because the code needs a tool. The guide rides along because the work needs a witness.
This is what co-change reveals that a dependency graph cannot. Two files can be bound tightly together and never once refer to each other — bound not by imports but by the habit of being finished in the same breath.
core sample · the most-companioned files
A manifest disturbed by everything that needs a tool. A guide disturbed by everything that needs explaining. Neither is a feature; both ship in every feature's company.
Nothing reaches the surface alone. The reaching-sideways is the work too.