[mjw1007]

I found this part interesting: «Please also provide insight in the legal grounds for transferring my personal data to these jurisdictions.»

Do you know if there's really a requirement to provide requestors with your beliefs about the law, or with legal advice you've received?

[sharkdaysunrise]

This language refers to the specific grounds established by chapter 5 of the GDPR under which transfer is allowed. The data subject is expecting you to point at the specific clause that provides legal grounds in your case.