72.0.3626.8
Firmware: Google_Cave.7820.384.0
Steps:
1. Download a file, Screen Reader should announce the download is successfull.
and then 

2. Navigate to the Downloads bar with F6
3. Open the downloaded file. 
Expected: ChromeVox announces a download has started and when it is complete
Actual: ChromeVox does not announce anything
Reproduces in Dev