Rated 4 out of 5 stars

Please, add displaying file size and bitrate for music for VK music, thank you

This review is for a previous version of the add-on (0.3.9.1). 

It's already here. Please, have a look at extension preferences (“Music” section). Do also consider upgrading to the most recent version:
https://addons.mozilla.org/firefox/addon/vkontakteru-downloader/versions/0.3.9.4pre