What are some four-letter file formats?

21 of the 56 file formats in Icillion have exactly 4 letters, for example DOCX, XLSX and JSON.

Which four-letter file formats start with A?

A is the most common first letter here, with 3 names, such as APNG, AVIF and Avro.

Computer Science · lists

These are the four-letter file formats in Icillion: 21 names, from “APNG” to “YAML”.

21 of the 56 file formats have exactly 4 letters (38%).
Most start with A (3), C (2) and D (2).
Only names of one word are counted, and only their letters: spaces, hyphens and apostrophes are not.

What are some four-letter file formats?: 21 of the 56 file formats in Icillion have exactly 4 letters, for example DOCX, XLSX and JSON.
Which four-letter file formats start with A?: A is the most common first letter here, with 3 names, such as APNG, AVIF and Avro.

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