As a heads up, since I saw "application/x-shockwave-flash" appear in my email as a reply notification to this thread:
Flash Player will be blocked in all the major desktop browsers before 2020-12-31
There is zero support for Flash on Android or iOS (iPhone/iPad)
July 2019: Flash Disabled by Default in Chrome 76+
Dec 2020: Flash Support Removed from Chrome 87+
"Adobe is finally planning to kill off Flash once and for all. Chrome, Microsoft Edge, and Safari have all been blocking Flash over the past year, but Adobe is now planning to remove support for it fully by the end of 2020. "https://www.theverge.com/2017/7/25/16026236/adobe-flash-end-of-support-2020
There are hundreds of Google search result pages for this news. I've only posted two from the first page.