Apple Sr. Software Engineer interview questions

Terrible communications on the recruiter side from the start, though maybe just how Apple does things? After applying, weeks later I got a mostly generic email saying that a recruiter wanted me to send over availability for a WebEx technical interview. No additional details nor questions or a call on the role/my background, just straight into interview scheduling. I had no idea who I would be chatting with or what sort of interview it was and was told "due to Apple's confidentiality practices, we cannot provide the names of the interviewers you will be meeting with". Technical phone screen itself was good with a DSA question (more on "can we do this better/optimize" on the data structure side vs doing complex algorithms). The interviewer seemed equally confused, and asked if he should ask me a question and didn't know if I was going through onsites vs initial screens. I didn't pass, and had to follow-up weeks later to find out I was rejected.