.css
2 claimants
2 primary
0 secondary
shared primary (2)
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.
287.2M
total files
155.8M
first seen 2021–2025 (54.2%)
2021
median year (half its files since)
Case variants in archive: .css (287.2M), .CSS (71.9K), .Css (7.2K), .cSS (39), .CSs (26), .csS (21), .cSs (3), .CsS (2) — aggregated above.
Attribution status
This extension is attributed to css; Css script as primary by 4 authoritative claims.
Claimants (4)
Languages that list
.css among their extensions. Strength reflects whether the upstream source treated it as their primary extension.| Language | Source | Strength |
|---|---|---|
| css | linguist | primary |
| css | pygments | primary |
| css | wikidata | primary |
| Css script | pygments | primary |
Wikidata says… (7)
File formats, image formats, audio codecs and other non-PL
entities that claim
.css 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.
| Format | Class (Wikidata P31) | Suggested label | MIME | Notes | Action |
|---|---|---|---|---|---|
| Cartoon Studio Script Q105849769 file format | file format | — | text/plain | — | Use as new PL ↗ |
| Cascading Style Sheets file format family Q27826463 file format family | file format family | — | text/css | — | Use as new PL ↗ |
| Cascading Style Sheets Level 1 Q27826464 file format | file format | — | text/css | — | Use as new PL ↗ |
SWH-mined examples (0)
No archived examples for .css in our local mirror yet.