Calling it "Twitter's HTML Source" or "Twitter's HTML Source Code" would be reasonably clear. But just saying "Twitter's Source Code" does imply something other

Calling it "Twitter's HTML Source" or "Twitter's HTML Source Code" would be reasonably clear. But just saying "Twitter's Source Code" does imply something other than that, probably non-public backend code, you're right That would make me wonder about the interviewer's experience. That's not a feeling you want to have at the start of an interview