# microsoft/referencesource

Source from the Microsoft .NET Reference Source that represent a subset of the .NET Framework

Repository: https://github.com/microsoft/referencesource
Canonical: https://ross.abutalabs.com/products/referencesource
Homepage: https://referencesource.microsoft.com/
Language: C#
License: MIT
License Family: permissive
Last push: 2025-10-15T16:26:37+00:00

## Health v2 (maintenance only)
Score: 44/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 47, release rhythm 8, longevity 100
- inputs: {"age_days": 4312, "days_push": 322, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3444, forks 1301 (observed 2026-08-28T04:08:05.165361+00:00)

## What it is
A read-only mirror of the Microsoft .NET Framework Reference Source, containing source code for a subset of the .NET Framework class libraries. It is published under MIT for community reference and consulted during .NET Core development.

## Use cases
- browse the source code of .NET Framework class libraries
- understand how BCL types like System.Data or System.Core are implemented
- consult original .NET Framework sources when developing .NET Core
- look up reference implementations of .NET APIs
- study Microsoft's C# class library code for learning

## When to choose
- you need to read the actual implementation of .NET Framework library code
- you're porting or comparing .NET Framework behavior to .NET Core
- you want MIT-licensed reference sources for study or tooling

## When to avoid
- you need actively maintained .NET libraries - use dotnet/runtime instead
- you want to file bugs or request features - this repo is read-only
- you need a runnable NuGet package rather than source code

## Facets
- artifact type: library
- maturity: maintenance
- function: developer-tools, documentation
- domain: programming-languages, developer-tools, documentation
- platform: dotnet, windows, cross-platform
- tags: dotnet-framework, reference-source, read-only, microsoft, csharp, class-library-source

## Member repositories
- microsoft/referencesource (main) score 44

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:05.165361+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:37:37.413558+00:00, confidence not recorded.
  - readme: https://github.com/microsoft/referencesource (fetched 2026-08-28T04:08:05.165361+00:00, sha fb38b4bb4575)
  - homepage: https://referencesource.microsoft.com/ (fetched 2026-08-29T09:31:29.084307+00:00, sha 59b912d4949c)
- Data as of 2026-08-30T08:39:29.467469+00:00.