A copy of a Git repository (or set of repositories) hosted on GitHub that tracks an upstream source repository elsewhere, typically maintained for redundancy, visibility, or community-engagement reasons rather than as the canonical primary copy.

ByCASRAI Editorial Board

· Last updated 10 Jul 2026

Examples

Worked examples

Is an instance
The Linux kernel's official GitHub mirror, tracking kernel.org's git tree.
Is an instance
An institutional repository mirroring its internal GitLab projects to GitHub for community engagement.

Counter-examples

Looks similar, but isn't

Not an instance
A fork created independently with no automated sync from upstream is not a mirror.
Not an instance
A clone on a developer's laptop is not a mirror.

Editorial commentary

GitHub-mirror arrangements are common where a project’s canonical repository lives on a self-hosted Git server, GitLab instance, or institutional Gerrit installation, but a public mirror on GitHub is maintained for ease of discovery, issue-tracking by external contributors, or CI integrations. Pushes flow from upstream to mirror via scheduled jobs or webhooks. For long-term preservation, the upstream is the canonical artefact; the GitHub mirror is a working convenience.

References

GitHub documentation, 'About repository mirroring' (docs.github.com).

Also known as

GitHub read-only mirror

Machine-readable encodings

Use in your systems

JATS XML <role> element

xml

<role vocab="credit"
      vocab-identifier="https://casrai.org/dictionary/"
      vocab-term="GitHub mirror"
      vocab-term-identifier="https://casrai.org/dictionary/term/github-mirror" />

Schema.org DefinedTerm (JSON-LD)

json

{
  "@context": "https://schema.org",
  "@type": "DefinedTerm",
  "@id": "https://casrai.org/dictionary/term/github-mirror",
  "name": "GitHub mirror",
  "identifier": "https://casrai.org/dictionary/term/github-mirror",
  "description": "A copy of a Git repository (or set of repositories) hosted on GitHub that tracks an upstream source repository elsewhere, typically maintained for redundancy, visibility, or community-engagement reasons rather than as the canonical primary copy.",
  "inDefinedTermSet": "https://casrai.org/dictionary/domain/data-infrastructure#set",
  "url": "https://casrai.org/dictionary/term/github-mirror",
  "sameAs": [
    "GitHub read-only mirror"
  ],
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "publisher": {
    "@id": "https://casrai.org/#organization"
  },
  "dateModified": "2026-07-10T02:06:21",
  "inLanguage": "en"
}

Referenced across the research world

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