Adobe announced in 2017 that it will stop supporting Flash at the end of 2020. In the latest Safari Technology Preview released by Apple, Flash support is officially discontinued.
Introduced in 2016, Safari Technology Preview gives users an early look at upcoming web technologies in macOS and iOS. It's a standalone app that works alongside the latest version of Safari.
Flash support has been discontinued in Safari Technology Preview 99, which means that Flash cannot be installed and used in Safari.
Apple stopped pre-installing the Flash plug-in on Mac computers as early as 2010. Users need to install and download it from Adobe's official website by themselves if needed. In macOS Sierra, Apple disables Flash by default.
Flash was once ubiquitous on the web -- the Flash runtime was installed 500 million times in the second half of 2013.
The death of Adobe Flash has been years in the making. Back in 2017, Adobe announced it would stop supporting Flash by 2020. Along with Apple, Microsoft, Google and Mozilla all announced their plans for retiring the technology in their respective browsers.