(registered 2026-07-20, last updated 2026-07-20)

Scheme name: ust

Status: Provisional

Applications/protocols that use this scheme name: The Universal State Transcript (UST) protocol uses the "ust" scheme as the time-frame coordinate that identifies every UST record.
A "ust" URI names a UTC time frame -- an hour, a minute, or a second -- in the form ust:YYYYMMDD.HH[MM[SS]] (for example ust:20260424.15, ust:20260424.1530, ust:20260424.153045); a coarser frame is a literal string prefix of every finer frame it contains (hour contains minute contains second). The scheme is an identifier, not a locator: a "ust" URI does not by itself dereference to a network resource; a frame is resolved to a signed record out of band by the UST protocol. 
Open-source reference implementations are published on npm as "ust-protocol" and "@ust-protocol/*", and the scheme is used in a production deployment at https://noosphere.md .

Contact: Evgenii Cherniakhovskii, e.chernyakhovskiy&gmail.com

Change controller: THE LAB, https://thelab.md, thelabmd&proton.me

References: Universal State Transcript (UST) Protocol specification, Section 8 ("ust_id frame identifier"), which defines the scheme's syntax, semantics, encoding, and security considerations:
https://github.com/thelabmd/UST-Protocol/blob/main/spec/UST-1.0.md

Repository and reference implementations: 
https://github.com/thelabmd/UST-Protocol