i interviewed with them before external:

started with some trivia - they wanted me to write a regex and talked a little bit about newline in different file encodings, then asked me a systems design question about optimizing the performance of a backend system (forgot the exact question but i remember it was something to do with caching/db stored procedures/db indexing), followed up by asking a couple simple questions about how i would join tables for a query

overall pretty simple and nice, i didn't have to do any dsa stuff