Source: Chrome Web Store and Ext Watch checks. “—” = not tracked yet.
Audio Booster for Youtube [QVI] at a glance
Audio Booster for Youtube [QVI] is an Entertainment extension by HideApp with ≈2K users. Chrome Web Store users rate it 4.4 out of 5 from 5 ratings, which is still a small sample. By users it sits in the top 5% of Entertainment extensions. It was updated 12 days ago.
It works, the extension collects EXCESSIVE amounts of personal information and tries to prompt users to do some survey to "help Hollywood produce shows and movies". This extension's privacy policy states it tracks your viewing history, how long you watch videos, your location etc. Very sketchy. An audio booster shouldn't need so much personal data just to control the volume of a Youtube video, they openly admit to selling our data to businesses, partners etc. too.