Open Data Day Moscow 2020
See the web-based schedule if you don't trust apps and calendars. Otherwise, choose a section for your device.
On an Android phone, install the Giggity app (scan the first code), start it and click on a "+" button, then click "Scan QR" and scan the second code. Or copy the XML link if you're reading this on a phone.
iPhone or iPad
On an iOS device, simply start a camera and scan the code below. It will add all conference events to your calendar. Or click on an iCalendar link. You can easily disable and delete the section afterwards.