I read the ruling. It is apparently because of this law in the US statutes: https://www.law.cornell.edu/uscode/text/28/1782 which authorizes a judge to "order [some person] to produce a document or other thing for use in a proceeding in a foreign or international tribunal ... The order may be made ... upon the application of any interested person"
It is mostly up to the judge's discretion, but case law establishes 4 discretionary factors to consider: 1) whether the request is from a potential lawsuit participant, 2) nature of the tribunal 3) whether discovery can be obtained by other means, and 4)whether compliance is burdensome.
It is mostly up to the judge's discretion, but case law establishes 4 discretionary factors to consider: 1) whether the request is from a potential lawsuit participant, 2) nature of the tribunal 3) whether discovery can be obtained by other means, and 4)whether compliance is burdensome.