I dimly recall a pre-form web, but it could easily be they just took over a little-used Berners-Lee verb. (For instance, PUT support was atrocious for a while.)
This is not about pre-form web. It's about pre-CORS web. Which is pretty recent web. CORS was "widely & properly" supported by "recently released" browsers around 2012-2013. Of course it's only as of very recently that you could safely assume 2010-2013 browser versions were completely out of circulation.
My bad; hadn't parent'ed enough, and the "using different methods than GET" clarification would not have been anachronistic even in the previous century.
PUT can still be weird. For example, PHP doesn't process multipart/form-data if it's a PUT instead of a POST, I'm working on an API in Laravel and for methods that need to PUT a file I have to use Laravel's _method spoofing.