The machine-readable contact details are published at /.well-known/security.txt, in the format defined by RFC 9116. That file is the authoritative contact point; if anything on this page and anything in that file disagree, the file is correct.
When you report an issue, the most useful things you can send are the affected version or commit, the deployment shape, a reproduction that does not require access to another institution’s data, and your assessment of impact. Please do not include customer personal data in the report itself.
Testing must be against your own installation or a test tenant you have been granted. Do not attempt to access another tenant’s data, degrade a production service, or exfiltrate records to demonstrate an issue — the acceptable use policy covers this in more detail.