I just found out about this. To be honest, I hadn't accessed it in forever but I thought it was kind of cool that you had a choice to enable or disable plugins. Well, no more. For PDF view and Flash, you can still disable them in the Settings area. But anything else, I guess you're out of luck. It also effects Chromium, the open source browser that Chrome is based on.
https://www.ghacks.net/2017/01/29/google-removes-plugin-controls-from-chrome/
Oddly, that seems to coincide with the newly-released Firefox 52's complete removal (ALMOST! <^8#) of support for plugins in favour of the move to web... what the he!! was it called again?
ALMOST, because plugins (Java, etc.) won't work any more (EXCEPT FOR Adobe Flash!!) ??
Sometimes it's HARD to take that leap of faith that technology is evolving, against the adage, "If it works, DON'T FIX IT!" <^8#
(...webAPPs... webClusters... encapsulated modules, I believe... Pogo's gonna have a COW! <^8#)
Evidently, one short-term fix for Firefox is to switch to the ESR version. Since it's extended support, it probably won't drop the support for NPAPI plugins for a while, maybe even a long time since some enterprise clients use Java web apps for their business.
Yeah, but that simple contrivance breaks the "it just works" mantra of most Linux distros, and requires intervention, something even I can't be bothered with - and, on another note, I'm led now to understand that the upgraded Flash Players (v24+) don't work on some (older) computers due to shortcomings in the CPU, not, as I've been trying to surmount, anomalies in subtle dependencies not met and not identified by the OS/pkg. mgmt. system(s)...
Case in point: I've had issues for some time with Linux Lite, MX Linux, elementaryOS, etc., not working with the newer versions of Flash Player, so I decided to find a one-shot solution for all. Enter Lubuntu. I started on a particular older system with 12.04 (no subscript) and it loaded fine, Firefox worked, and so did the newest Flash Player (25...) I did the in-place upgrade to 14.04.5, and everything remained functional. I went back and reinstalled using the 14.04.5 DVD, and the latest Flash Player *didn't* work...??!?? Also, in the 12.04 load, man 3 strftime has an entry in the manpages; in the fresh install of 14.04.5, it doesn't...
I have another tower that Lubuntu simply WOULDN'T load successfully onto, *SO* I put that HDD into the previous, did the load, swapped it back into its original system and all was well, BUT... Flash Player doesn't work without backpedalling to 11.2.202.644...
It appears, in conclusion, that older computers have been left behind by the advance of new (or upgraded) tools...Even for Linux...
And the punch line in this? Firefox crashed without the Flash Player backpedal. Chrome/ium (can't remember which) ALSO crashes - and DOESN'T appear to have a link to the Flash Player plugin which could be pointed to as the reason, AFAICT. So, effectively, I have THE TWO browsers in Linux that will not operate at all...