Well you can somewhat calculate the CO2 emitted by a parcel shipped from X to Y. Of course it will depend on loads of factors, like did they use a plane, a truck, a barge with one guy sitting inside rowing gently down the stream, etc… so im not sure how exact their numbers will be.

Basically it means nothing anyway, but companies love to tout how “green” they are, dont they?

Would you mind sharing your credentials and domain expertise on the topic?

Good point, better not try.