They seem to be a significant target for DDOS attacks, which seem to have been quite frequent. That uptime measure is for the application server, which I suspe

They seem to be a significant target for DDOS attacks, which seem to have been quite frequent. That uptime measure is for the application server, which I suspect does not include GitHub Pages which is hosted separately on static content servers. Lastly, 99.9% uptime over a month means 43 minutes of downtime. To me, that sounds like quite a lot.