That Famous WebComic (TFWC) is a viewer app for XKCD. It takes the atom feed of XKCD and displays the most recent episodes. XKCD is a webcomic by Randall Munroe. Please refer to http://xkcd.com/about/ for more details. TFWC is just an alternative way of browsing the comics. So, all credit for the comic itself goes to Randall Munroe.
The app is implemented using different technologies and platforms. These implementations reside in corresponding subdirectories. All are distributed under the terms of the GNU General Public licence v3 as published by the Free Software Foundation.
The app in the subdirectory gluon is based on Gluon Mobile. Please refer to http://gluonhq.com/products/mobile/ for more details. It deliberately does not use Gluon Glisten but a humble JavaFX interface for the sake of exercise ;-).
Flutter apps are written using the Dart programming language. Please refer to https://flutter.io for more information about Flutter.