Edit `--1013` is 13 Oct in any year: https://en.wikipedia.org/wiki/ISO_8601#Truncated_representations https://en.wikipedia.org/wiki/ISO_8601#Truncated_represent

Edit `--1013` is 13 Oct in any year: https://en.wikipedia.org/wiki/ISO_8601#Truncated_representations https://en.wikipedia.org/wiki/ISO_8601#Truncated_representat... (`--01-14` is Jan 14 in any year, the last dash is "optional"). The "duration" (`P`) and "repetition" (`R`) syntax is also pretty wild.