Language extensions are used to enable language features that are not part of the official Haskell report, but extend the capabilities of the compiler.
TODO: Reach out to authors of guides below to request usage of content.
TODO: How To Enable Extensions (see https://www.schoolofhaskell.com/user/PthariensFlame/guide-to-ghc-extensions/how-to-enable-extensions)
TODO: Fold in Basic Track from Jannis' guide.
TODO: Link to official GHC docs for extensions.
An Opinionated Guide to Haskell in 2018 - by Alexis King
A Guide to GHC's Extensions - by Jannis Limperg
What I Wish I Knew When Learning Haskell - Extensions - by Stephen Diehl
Guide to GHC Extensions - by Alexander Altman