What "confidential" means here
The material behind the share link (a cut, a screener, a work-in-progress) is confidential. Treat it the way you would treat any unreleased film or television material you receive from a studio under an industry NDA, even if no separate NDA has been signed.
Specifically: do not download, copy, screen-capture, screen-record, photograph, or transcribe the material. Do not show it to anyone else. Do not discuss its contents publicly, including on social media. Do not use it for any purpose other than the one for which it was shared with you (review, awards consideration, festival submission, casting feedback, financing review, etc.).