yes! gets the job done

some websites send certain files with an "attachment" header and firefox shows a popup-dialog to "open with X or save file", even for files that firefox could display, like *.htm or *.jpg or *.pdf or *.mp3

here is a test page:
http://test.greenbytes.de/tech/tc2231/#attwithasciifilename

that behavior is desired in some cases, with large files or with actual "download links", but mostly its annoying and we just want to see the file ....

.... and find this addon to silently "rewrite" the disposition header. no more popup, just shut up and show me your bits!

via
https://stackoverflow.com/questions/3251575/how-to-ignore-content-disposition-attachment-in-firefox