SOLVED: 1.5RC - White screen after updating from 1.5-beta to 1.5-rc on frontend and backend

Is it possibly related to the other issues people have been reporting lately with the white screen showing?

Seems the usual cause is Rocket Loader in Cloudflare, and also third-party software such as BricksExtras (which an update was published which resolved it already too if using BricksExtras).