Information costs money to generate and store and has value. Many companies consider information a form of asset. Proprietary information is information which a company or organization owns or is the proprietor of. This term is used primarily in a legal sense, just as "property" and "ownership" are ideas carefully defined by law. Normally it refers to new knowledge generated within the organization which can be legally protected from use by others. A rough synonym for "proprietary information" is "trade secrets." A trade secret can be virtually any type of information which has not become public and which a company has taken steps to keep secret.
Jason has no proprietary right to the information developed by Prof. Nice and in whose development he participated in a minor way. That information is proprietary to the university or the sponsor who funded the research work. Some agreement prior to the initiation of a research project must be developed (and adhered to) about to whom the data and information assembled during the project belong. When Prof. Nice receives a request from Jason he must get clearance from the owner of the proprietary information before sending a copy to Jason. The only case in which this would not be necessary is if the university/Prof. Nice arrangement grants ownership of the information contained in the report to Prof. Nice. Even in that case, it is unwise to send the information to Jason without a clearly defined explanation of just what Jason intends to do with the report.
When Prof. Nice finds out what Jason has done with the report he must admit the error he made and inform authorities at the university that granted Jason his degree of this flagrant case of plagiarism (passing off of another's work as one's own). Hopefully, this step (which is a form of "whistleblowing") should lead to the action granting Jason a master's degree being rescinded. Where were the university supervisors of Jason's graduate work when this plagiarism was happening?
A case somewhat similar to this occurred at a company for which I worked. An employee left voluntarily to go to graduate school. Due to some slipshod handling of his "exit procedure" by the Human Resources Department, the fact that he had taken his laboratory notebooks (containing company proprietary data) was not discovered until several weeks after his departure. Letters asking him for his notebooks, which contained proprietary (and sensitive) data on the flammability of plastics, were ignored. A couple of years later he received a Master's Degree in Chemistry from a reputable university. Major portions of his thesis bore strong resemblance to the research work he had done for the company at which I worked. We chose to take no action because we felt we could not prove his plagiarism in court if a legal action developed.