>why check mime type of handout?

To check if current file is rewritten by another one. See [video_handout.feature](https://github.com/edx/edx-platform/blob/anton/download-handout/cms/djangoapps/contentstore/features/video_handout.feature#L69)

>Does Studio provide correct mime types for all types of files?

We have a direct link to the file and I'm using `html` and `pdf` files in tests that has correct mime types (`text/html`, `application/pdf`).