@prologic@twtxt.net For what it’s worth, the twt hash extension is specifically modeled after yarnd’s implementation with all the quirks coming from Go’s stdlib: https://twtxt.dev/exts/twt-hash.html#timestamp-format

“All timezones representing UTC must be formatted using the designated Zulu indicator Z rather than the numeric offsets +00:00 or -00:00. If the timestamp does not explicitly include any timezone information, it must be assumed to be in UTC.”