Diagram-js library is MIT licensed, but bpmn-js?

having problems to match
https://bpmn.io/license/
with https://choosealicense.com/licenses/

could you please help and return the license name for bpmn-js?

The name of the bpmn-js license is bpmn.io License (as clearly stated in the license header).

clearly stated :slight_smile:
If you call it “Open Source” without using an approved license, you will confuse people.
https://opensource.org/faq#avoid-unapproved-licenses