I am running Firefox 129.0.2 (64-bit) on Ubuntu 20.04.4 Recently, I have been browsing a StackExchange site and hit the back button of the browser several times (still remaining on StackExchange). I then realized that upon the last button click, Firefox downloaded a weird HTML file called something like ha71ksd.htm. The file was empty (0KB) and when uploading it to VirusTotal it showed me a completely different file there (probably since the hash of an empty file is always the same). In any case, I am a bit worried that I might have been infected by a virus. Therefore, I'd like to at least reproduce what happened. I read in different places that it might have something to do with a wrong MIME type reported by a server prompting Firefox to download instead of displaying a file. But Stackoverflow having such a misconfiguration is also strange. I know that a 0KB file cannot contain anything malicious but the whole incident seemed highly suspicious and I need to find out what happened. Any help or tips are appreciated!