Rated 5 out of 5 stars
For anyone with a older machine (slow) and uses tons of tabs, Brief is certainly welcome addition. Anything that opens as sidebar for me tends to be a sluggish but Brief is light fast always.
As for no documentation. It seems that this addon is as "simple" as it gets. Add feeds to the "Live Bookmars" folder, or wherever you store your feeds at in the bookmars. Go to the options in Brief window, Feeds tab, then select the feeds folder.