Yes, we were streaming for 24h about Liferay DXP and Liferay Portal 7.3 (and previous versions). All kinds of technical information that might be of interest for you. You might have missed it, but luckily we have it all recorded - and the recordings are available for you:
The new Community Site (also called Questions) was built using React + GraphQL served and using Liferay.
We'll see how to build a similar site and many tips regarding React in Liferay, how to interact with the GraphQL endpoint, use permissions, combine queries, use Apollo... everything powered by Liferay.