What documents are required to enter the Czech Republic for medical treatment?

Israeli citizens can now visit the Czech Republic but tourism is not officially permitted:

Travel for the purpose of tourism, or visiting friends, is not yet possible. Protective measures of the Ministry of Health of the Czech Republic include the closure of hotels and other accommodation facilities. Among essential travel belong e.g. business meetings, exigent official meetings, court proceedings, care for children and family members, necessary hospital treatments, accompanying family members, attending funeral service, participation in education, university exams, participation in gatherings that were approved by the Ministry of Health.

If one is coming in for a medical treatment, what exact documents are required to be shown at the border?

NB: I will answer this question from personal experience within two weeks. Adding it here in case someone already knows the answer.