Okay! Still a big question:
According to Gabriel Aul, as quoted Here (amongst many places), Microsoft will support the relatively new HEVC (High Efficiency Video Coding) video compression standard in Windows 10 out of the box.
Back to the question:
Where is this support?
Windows Media Player and the Film & TV (Movies & TV) app do not support HEVC playback in the current build 10240 (RTM or not RTM?!?!) fully updated as of 23rd July! In earlier builds, such as 10074, WMP did support this format, so what happened?
Are we going to get HEVC (x265) support, or are we still going to have to install codec packs on Windows 10?