few notices:

- publishing single file propagates to gateways way better than publising directory

- use ?file=file.ext query parameter to add correct mime type

here you can see, if you exclude filename, it will download as zip, but with filename parameter it stays as xpi and installs as ff extension

nostr:note1sgsd7w52887qs5eu2sut3g0s5v0kf3mpe4p779ma2j5ezmrsksjsljqxjx