Fun fact, all US customary units are defined in terms of the metric system. For example, 1 inch is exactly 2.54cm. which means a US mile is 1.609344km. Americans have be using a bastardized version of the metric system since 1959.

https://en.wikipedia.org/wiki/United_States_customary_units

One thing to note, aside from all the other inconsistencies, that tracking number does not follow the standard tracking number format for a USPS package. The USPS website describes their different tracking numbers for their different services in the FAQ at the bottom of their tracking page. https://tools.usps.com/go/TrackConfirmAction_input