Current version (1.98.2 updated on 28/2/2018) works (at least on YouTube) without asking for too much permissions or installing 3rd-party plugins/apps/software
However,
1. You have to manually reload YouTube pages to find any video or update the download list
2. 720p max. It couldn't download 1080p or resolutions with incomplete address (without 3rd-party apps/software)
3. (related to pt.1) It will download the previous video if you don't reload the entire page before clicking on the green arrow