On Chrome Windows (at least), this gives a discrepancy between opening (.bin and text/plain give what I would expect):
And saving using the file handle given by the above fileOpen (same options):
I opened a .bin file, so the MIME type application/octet-stream (I assume) was used and suddenly Windows is prompting me to save the file as a .exe too!
fileSave (unlike fileOpen) with the new API doesn't implement
options.mimeTypes: https://github.com/GoogleChromeLabs/browser-nativefs/blob/f7cb5883c87d179f705e93414c351e1d363641f0/src/nativefs/file-save.mjs#L31On Chrome Windows (at least), this gives a discrepancy between opening (
And saving using the file handle given by the above 
I opened a
.binandtext/plaingive what I would expect):fileOpen(same options):.binfile, so the MIME typeapplication/octet-stream(I assume) was used and suddenly Windows is prompting me to save the file as a.exetoo!