The -li Ending, basically just the diminutive, is not necessary to convey the meaning. -br is "cold", -brot is "bread", -brotli is also "bread". I kind of like the whole archive.bread thing, but with the German sound to it.

but we don't want to type them. when was the last time you typed chdir instead of cd?

when was the last time you were in a shell that didn't have tab completion?

.br<tab> is the same number of characters as .bro

Filename autocompletion is a thing though, and especially for .brotli files, which would likely be generated by something like `brotli uncompressed.thing`, the length matters very little.