And fnt has little to do with apt; it's a wrapper around curl + ar + tar, that doesn't support any of the important features of APT (signature checking, dependencies, updates, keeping track of what is installed, uninstalls, ...)
that is true. but everyone knows apt, so if you want to explain something similar in usage, i'd refer to something people know about. of course your description: "wrapper around curl/ar/tar" is on point, but would anyone have understood it? the missing important features are a good idea.