When accessing the keyfiles, no content type is set. The browser may try (and fails) to interpret them as html. https://github.com/ENOFLAG/ENOKEY/blob/19620841183e93948a82d470e251953ff0db2e41/src/main.rs#L368 
When accessing the keyfiles, no content type is set. The browser may try (and fails) to interpret them as html.
ENOKEY/src/main.rs
Line 368 in 1962084