Thought experiment: someone gives you a hard drive with some music and video files on it...but you have no idea what a hard drive is, or what music and video files are, or what a file format is.
Beyond a certain level, you can only reverse engineer tech if you already know almost everything there is to know about how it works, or you're vastly smarter than the original designers - by at least a couple of orders of magnitude.
I can't imagine anyone alive today being able to solve the hard drive problem, or an alien equivalent, from scratch.
You'd have to be able to work out the basic physics of magnetic storage, the disk-level coding system used, the higher level file and data organisation, the chip design in the drive firmware, the code in the firmware, the rest of the drive electronics, the coding and compression systems used for audio and video data (how do FLAC or H.265 work on the inside?) - and you'd only be able to do all that if you understood that the hardware target was a modulated gas compression reproduction system with a certain frequency range intended for use in an atmosphere with specific characteristics, and a planar display technology with a similarly limited ability to generate a moving pattern of electronic magnetic frequencies.
And even if you could decode and view the cat videos on the drive, you probably still wouldn't find them funny.