Regarding backreading (and fowrard too, honestly)... you can store files in .zip (ie not compressed at all). Some of those files could be a pretty valid .zip files too. *grin*
An other fun trick is that zip being back-read means it can be smushed together with a file that’s forwards-read, and you get a dual-format file. That was a common way to smuggle archives on image boards.
pico-8 does that by design, the “cartridges” are image files, except it uses steganography to encode the program in the image instead of just smuggling.
this is also how self extracting executables work. It's just a program that extracts whatever zip file exists after the program itself. Rename it from exe to zip and you have a valid zip file that just happens to have windows executable code before the start of the zip contents
