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Contents Indices

A contents index is a repository-level listing that maps every installed file path to the package that ships it — the answer to "which package would put usr/bin/convert on my system?" before anything is downloaded. Distributions publish it so that file-level questions can be answered from repository metadata alone: utilities like apt-file and dnf provides are built on it, and it is the only way to resolve a dependency or a request phrased as a file path back to an installable package.

The line format

Every family's listing reduces to the same fact — one path, one owner — but Debian's format is the canonical example: a whitespace-separated path and a qualified package list, one file per line, no leading slash.

usr/bin/bash                                            shells/bash
usr/share/fonts/truetype/dejavu/DejaVuSans.ttf          fonts/fonts-dejavu-core
etc/passwd                                              base/base-passwd,admin/passwd

What each family publishes

Family Listing Scope
Debian dists/<suite>/main/Contents-<arch>.gz and dists/<suite>/main/Contents-all.gz split: per-arch carries architecture-specific packages only; Contents-all carries every Architecture: all package
Ubuntu dists/<suite>/Contents-<arch>.gz (suite level) merged: each per-arch file includes Architecture: all packages
RPM (CentOS, Fedora, Alma, Rocky, openSUSE) repodata/…-filelists.xml complete: every package's files, all architectures the repo serves
Arch / CachyOS <repo>.files database complete per repository
Alpine — none: APKINDEX carries no file lists; only so: (libraries) and cmd: (commands) are discoverable, through the provides namespaces

Debian's split: per-arch plus Contents-all

Since the Contents-all split (Debian 9 "stretch"), Debian's per-arch listing on the live mirrors deliberately excludes Architecture: all packages. The consequence is easy to underestimate: fonts, icon themes, time-zone data, documentation, and most pure-Python libraries are all Architecture: all, so a consumer reading only Contents-<arch> sees none of their files. Measured against bookworm on deb.debian.org: Contents-amd64 holds zero entries under usr/share/zoneinfo/ (tzdata), zero under usr/share/fonts/truetype/dejavu/ (fonts-dejavu-core), and zero for python3-requests' module tree — while Contents-all holds 1,265, 22, and 18 entries for the same prefixes respectively. Both files must be read for full coverage; the two are disjoint by construction, since a package is either architecture-specific or Architecture: all, never both.

The mirror lifecycle changes the layout

The same suite is laid out differently depending on which mirror generation serves it:

Mirror Per-arch Contents Separate Contents-all
deb.debian.org (current suites) split — arch-specific packages only published
snapshot.debian.org (dated pins) split, preserved as on the live mirror at that date published
archive.debian.org (retired suites) merged — Architecture: all entries are folded in on import removed, and absent from the suite's Release manifest

So a retired suite such as buster answers every file-ownership question from its per-arch file alone, and the Contents-all URL that worked while the suite was current returns 404 from the long-term archive — the file is genuinely gone there, not relocated. Ubuntu never splits in the first place: its suite-level per-arch Contents is always the merged form, on every mirror. A consumer that wants full coverage across all three mirror generations must therefore read both files where they exist and tolerate the absence of Contents-all where the merged per-arch file already carries everything.

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