@jasonpriem http://isni.oclc.org/sru/DB=1.2/?query=pica.isn+%3D+%220000+0004+0380+1313+%22&version=1.1&operation=searchRetrieve&stylesheet=http%3A%2F%2Fisni.oclc.org%2Fsru%2FDB%3D1.2%2F%3Fxsl%3DsearchRetrieveResponse&recordSchema=isni-b&maximumRecords=10&startRecord=1&recordPacking=xml&sortKeys=none&x-info-5-mg-requestGroupings=none

For years we found ISNI licensing was opaque, but as of 2020-06, they link to an "ISNI Information License."

https://web.archive.org/web/20200603143900/https://www.isni.org/page/objectives-and-policies/

Not sure how it now relates the subset called "Open-ISNI"- but seems API for that died in 2020-08