.w

2 claimants 1 primary 1 secondary unambiguous primary

SWH popularity

Distinct files in the full Software Heritage archive (2026-06-04 export), dated by first appearance, following Desmazières, Di Cosmo, Lorentz (MSR 2025). Case-aggregated. citation.

663.1K
total files
515.2K
first seen 2021–2025 (77.7%)
2023
median year (half its files since)

Case variants in archive: .w (660.9K), .W (2.2K) — aggregated above.

Attribution status

This extension is attributed to CWEB as primary by 2 authoritative claims.

Authoritative sources: ✓ Linguist ✗ Pygments · no claim ✓ Wikidata · Q5014842 ✗ Wikipedia · no claim

Disagree or have a correction? Open a labelling issue.

Claimants (3)

Languages that list .w among their extensions. Strength reflects whether the upstream source treated it as their primary extension.
LanguageSourceStrength
CWEBlinguistprimary
CWEBwikidataprimary
OpenEdge ABLlinguistsecondary

Wikidata says… (2)

File formats, image formats, audio codecs and other non-PL entities that claim .w on Wikidata (property P1195) or in the Wikipedia infobox. Source: data/derived/external_extension_index.csv. Click Use as new PL on any row to open the Add-PL form pre-filled with that entry's name, Wikipedia/Wikidata URL, and this extension — one submission creates the PL + claim.
Right entry isn't listed? Add manually ↗
FormatClass (Wikidata P31)Suggested labelMIMENotesAction
Applause Word data Q105856567
file format
file format—application/octet-stream—Use as new PL ↗
Work File Q116446363
file format
file format———Use as new PL ↗

Disambiguation rules (2)

Linguist heuristics that decide, by content, which language a .w file actually is.
RulePredictsKindPredicates (truncated)Measured on SWH
h/linguist/.w/0OpenEdge ABLpredicates[{"kind": "any", "regexes": ["&ANALYZE-SUSPEND _UIB-CODE-BLOCK _CUSTOM _DEFINITIONS"]}]
h/linguist/.w/1CWEBpredicates[{"kind": "any", "regexes": ["^@(<|\\w+\\.)"]}]

SWH-mined examples (1)

Real archived programs with this extension, byte-verified against the SWH archive, grouped by predicted language and by how the prediction was made. Useful for deciding what this extension actually is when the attribution is uncertain.
CWEB (1) — 1 via Linguist heuristic
medsched.w · 2987 B · seen 2× in SWH
predicted: CWEB via heuristic
swh:1:cnt:b4895ceb3eaaf0c305d6f907b03bca1041a8b497;origin=https://github.com/gchilders/lasieve5_nfsathome;anchor=swh:1:rev:3be451f1831f969899080b74602965df0cf57445;path=/athlon64/medsched.w
Open in SWH · Raw bytes
Request more SWH-mined examples
If the examples above don't disambiguate what .w is, request a fresh mining run.
(or open the pre-filled issue directly)