@FerdinCrypto It's actually very unexpected. I personally use Firefox 62 and no problem occures. Could you please contact us at bug@muonium.ee so that I may ask your more question without being restricted by the tweet length?
@_gabriele_p No, this isn't encrypted. But we plan to. Actually, encrypting the metadata would likely make crash the browser in the case the user has many files in just one folder. In any case, we'll release it out as a feature, later.