Login required, for something that absolutely doesn't need login. Might as well not even have bothered making it. Or at least they could have been transparent that they posted an ad for their product and not any actual contribution
They have example papers on the homepage you can use to see how it works, below "Upload your own paper"
If you made an account, could you upload Mochizuki's IUTT 3 and ask for an explanation? As far as I know, nobody understands that paper, so any enlightment would be welcome.