Code · dstl · UK Public Sector GitHub Observatory

Language figures come from GitHub's own per-repository byte counts, which measure source rather than a single headline label. File counts and repository sizes come from the mirrors themselves. The two tell different stories, and the difference is the point.

The codebase

languages in use

32.4 MB of source

10.4k

files at HEAD

across every analysed repository

0 B

on disk as mirrors

full history, every branch and tag

471.8 MB

largest repository

Human-Interface-Horizons

What stands out

One archived repository holds 60% of all the bytes.

Human-Interface-Horizons is 471.8 MB of git - a 2013 static snapshot of www.gov.uk, not source code. It single-handedly makes HTML the largest language by volume (15% of all source bytes). Any size or language statistic that does not exclude it is measuring an archive, not a codebase.

Sizes here are GitHub's reported figures.

This organisation was harvested with blobless partial clones, which fetch every commit and file path but not file contents, so there is no local size to measure against. Checked elsewhere in this dataset against 1,526 fully mirrored repositories, GitHub's reported size is accurate to within about six percent.

Ruby is the house language, but its share is falling.

Ruby is the primary language of 0% of archived repositories but only 0% of live ones. Python, Go, TypeScript and HCL have taken the difference - the signature of a shift from monolithic Rails publishing apps toward data pipelines, infrastructure-as-code and platform tooling.

Most repositories are small; a handful are enormous.

44% of repositories are under a megabyte of git data. The estate is not a monolith - it is a very long tail of small services, gems and prototypes around a few large publishing applications.

Languages, two ways

By volume of source

Bytes of code. Dominated by archived static HTML.

By number of repositories

How many repositories name each language as their primary one. A better guide to what engineers actually work in.

Live estate versus archive

The same language ranking, split by whether the repository is still active. The shift is the clearest signal of technical direction in the whole dataset.

Active repositories

Archived repositories

Scale

Repository size distribution

Git data per repository, log-ish buckets.

Commits against files

Each circle is a repository, sized by number of distinct authors. Both axes are logarithmic. The diagonal band is the normal relationship between codebase size and churn; outliers above it are long-lived apps with heavy iteration, below it are dumps and imports.

The shape of a repository

Directory layout is the cheapest reliable signal of what a repository actually is. app/ with config/ and spec/ is a Rails application; src/ with test/ is Java or Node. Counted by how many repositories contain each top-level directory at HEAD.

Most common top-level directories

Most common file extensions

By total file count across the estate.

The twenty largest repositories

Repository	Language	Git size	Commits	Files	Status
Human-Interface-Horizons	JavaScript	471.8 MB	33	324	archived
baleen	Java	100.5 MB	318	1,572	archived
Stone-Soup	Python	52.7 MB	6,902	751	active
IES4	-	40.9 MB	88	110	archived
sarcastic	C	26.4 MB	320	369	archived
Open_Source_ECOA_Toolset_AS5	Java	24.6 MB	22	1,148	archived
YAWNING-TITAN	Python	23.2 MB	2,085	440	archived
RET	Python	12.5 MB	16	752	active
muc3	HTML	3.5 MB	234	1,716	archived
eleatics	XSLT	3.4 MB	429	59	active
SAPIENT-Middleware-and-Test-Harness	C#	3.4 MB	12	193	archived
Stone-Soup-Notebooks	Jupyter Notebook	2.9 MB	24	13	archived
ideaworks	Python	2.7 MB	30	282	archived
NPIF-Sleuth	Python	2.0 MB	27	46	active
baleen3	TypeScript	2.0 MB	69	441	archived
Apex-SAPIENT-Middleware	Python	1.9 MB	7	242	active
lighthouse	Python	1.7 MB	1,145	565	archived
srup	C++	1.3 MB	45	180	active
BSI-Flex-335-v2-Test-Harness	C#	1.0 MB	17	533	active
re3d	-	419.8 kB	5	37	archived