rust port dep license need?

[Alex Talaran]

it seem only rust crate need license info. go and other ecosystem do 
not. is there a reason only this needed for rust? it seem to add 
complexity, time, and effort since it multiple to step to make crate 
list and then add license. maybe could be one step?

couldnt find on list but maybe used wrong terms.
https://man.openbsd.org/cargo-module.5 docs also lacks the info
thanks in advance