Spyglass expands on the ideas outlined in this paper by the Brave Search Team to allow users to define what should / should not be crawled and indexed for topics they're interested in.

Managing your library

Open the "My Library" window bygoing into the system tray menu and clicking on the My Library option. This will open a window like below:

Lens library window

Here you can view the progress of any crawls or lenses being installed. View Details will bring up the source code for the lens configuration.