At a conference recently, one person accidentally sent the organizer a pdf of their presentation with their notes underneath each slide, instead of the presentation itself, but it was super confusing because the file was "presentation.pptx.pdf" which of course got displayed by windows as "presentation.pptx". The person who decided to hide extensions by default must be so proud of pulling off such a wide reaching prank
Noob question: Could someone make e.g. an executable linkin park - numb.mp3 file on Linux by giving it execute permissions? Probably not by downloading, but by replacing the file with a duped one.
Also the .mp3.exe trick and the likes could be easily detected by any security software easily, like Windows Defender.