Code · britishlibrary · 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

82.4 MB of source

21.2k

files at HEAD

across every analysed repository

0 B

on disk as mirrors

full history, every branch and tag

429.8 MB

largest repository

peripleo-lanc

What stands out

One archived repository holds 21% of all the bytes.

peripleo-lanc is 429.8 MB of git - a 2013 static snapshot of www.gov.uk, not source code. It single-handedly makes HTML the largest language by volume (0% 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.

55% 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
peripleo-lanc	JavaScript	429.8 MB	654	257	active
fihrist-mss	XSLT	347.4 MB	2,607	14,583	active
BLL01	mIRC Script	215.8 MB	107	1,037	active
jpylyzer	Python	205.4 MB	603	86	active
UniversalViewer-old	JavaScript	187.5 MB	970	470	archived
examples	JavaScript	142.8 MB	1,026	645	active
Incunabula-Catalogue-Entry-Detection	Jupyter Notebook	131.0 MB	161	22	active
iiif-av-samples	CSS	128.4 MB	37	103	archived
locating-a-national-collection	PHP	44.5 MB	753	123	active
universalviewer	JavaScript	35.9 MB	3,845	614	active
uvAppDevNorthBL2023	TypeScript	34.0 MB	3,131	469	active
TremendousIIIF	C#	28.9 MB	85	95	active
blitter	Python	18.1 MB	109	73	active
jcpc-linked-data	JavaScript	13.9 MB	5	157	active
convert-a-card	Python	13.5 MB	46	259	active
data.bl.uk	HTML	12.2 MB	10	115	active
peripleo	-	9.2 MB	165	23	active
UniversalViewerExamples	JavaScript	6.4 MB	226	762	archived
BL-design-system	TypeScript	5.1 MB	49	154	active
nginx-vod-module	C	3.8 MB	1,178	286	active