To install Appimages from Appimagehub via CLI use appimage-cli-tool. This allows you to e.g. search appimages with "app search xyz" and install any appimage via command "app install #id".
If you are a developer who is interested to easily build appimages from your code repo, read the guide here.
Fluxbox is a stacking window manager for the X Window System, which started as a fork of Blackbox 0.61.1 in 2001, with the same aim to be lightweight. Its user interface has only a taskbar, a pop-up menu accessible by right-clicking on the desktop, and minimal support for graphical icons. Wikipedia