Attention! With this post I am not saying it is a wise thing to do but nevertheless you might need it for testing purposes.
Adobe Flash Player For Mac Install

Malware + Recommended + Security News. Mac Users Attacked Again by Fake Adobe Flash Update. Posted on April 12th, 2016 by Graham Cluley Mac users are once again being urged to exercise caution when installing updates to Adobe Flash Player, after a fake update was discovered infecting computers. After that, just go to Sys Prefs>Flash Player>Updates, which will show what version is installed. Running FF 48, or whatever the current, regular version is now, is as far as I know out of the question, since Mozilla no longer supports Firefox for 10.6 through 10.8, beginning 8/16.
Thanks David and Naoya!
On a Windows Server 2016 Datacenter Edition (with GUI) open the cmd line and type:
dism /online /add-package /packagepath:'C:WindowsservicingPackagesAdobe-Flash-For-Windows-Package~31bf3856ad364e35~amd64~~10.0.14393.0.mum'
(BTW. Adobe Package is already on disk. You just activate it)
+ Reboot
The results should be:
Download Adobe Flash Player For Mac
after the reboot verify in IE:
Adobe Flash Player Mac Firefox
and it seems we even get security updates just like for flash in IE on Win10: