Are time, timereceived and blocktime in UTC? I read around about the differences between time, blocktime and timereceived, but one question remains. Although I assume all times are UTC, I haven't seen that mentioning specifically anywhere.

Does anybody know which timezone the times in the bitcoin blockchain are formatted in? And does this also account for timereceived, or is that local?
All timestamps are in UNIX format, that is: the number of seconds since januari 1st 1970, 0:00 UTC.