What are the 5E origins of the Mind Flayers?


The 3rd Edition D&D sourcebook Lords of Madness says the illithid species originated in the distant future and somehow traveled to the distant past to avoid extinction. A trilogy of 2nd Edition modules says they came from another plane known as Penumbra without the time travel. Has the origin of these creatures been rewritten for 5th Edition, and if so, as how?