Whoa! That’s news to me.
What time capsule?
I don't recall if there's any date for it to be disclosed. The researcher who found out about it tried to get--I forget who--Nixon library's archivist or some such--tried to get them to pay attention to his evidence and search it out but was rebuffed & ignored.
I think the thought is that it is more of a letter than a box but there is some thought that there may be some UFO objects or tangible evidence in it.