I saw this 1-letter time convention in a bunch of places, the most relatable one is when you specify time spent on a task in YouTrack:
But is there an official name for it? Like you know, how P1DT12H is an ISO 8601 format.
The YouTrack seems to refer to it just as "Period Format", but that is too broad to use it out of context.
The reason I need this is that I have to pick a good name and specification link for a function that parses a string of this format, as our team chose it to represent durations in config files.
So far I'm going with the "Lettered Duration", but I wonder if there is a widely accepted name for this convention.
Related question: 'Human-readable' time short formats conventions?