It watches the folder ‘ambrowse’ inside HOME for newly written HTML files, extracts the metadata and removes the files afterwards. The metadata are added to a list in ‘books.yaml’. You can thus peacefully browse books online, but are not as tightly bound to the seller. You also have a temporal buffer, which allows you to rethink your impulse purchases. Pressing CTRL+S and Enter seem like a manageable workload compared to an in-browser solution.
[Caution: rant] It serves the same function as the older ‘amParser’ Firefox plugin, but is no longer bound to a particular browser. Mozilla made the usage of amParser more difficult by first requiring plugins to be signed by them (no thanks), before abolishing the old plugin system completely. Not only is the new plugin system IMHO poorly documented, it also seems downright impossible to write files to the file system, thus hindering interfacing with standard tools. Even if this were possible to accomplish by a sequence of magical incantations, I just don’t care about Mozilla any more. Adding to the DRM, data collection and advertising hassle, I bid them good riddance. Time for a saner alternative (which is definitely not Chrome).