Bug 1428733

firefox-52.0-3.el7_3

broken in 52.0-1
fixed in lates 52.0-3
https://brewweb.engineering.redhat.com/brew/buildinfo?buildID=541795

# rpm -qa | grep firefox
firefox-52.0-4.fc25.x86_64
============================
So I'm using Fedora 25, and with this last update of firefox, IcedTea-Web Plugin
is not recognized by firefox ,
while it is , with seamonkey 2.46 as viewed below:
=========================================
....
IcedTea-Web Plugin (using IcedTea-Web 1.6.2 (fedora-3.fc25-x86_64))

    Fichier : IcedTeaPlugin.so
    Chemin : /usr/lib64/IcedTeaPlugin.so
    Version : 
    État : Activé
    The IcedTea-Web Plugin executes Java applets.
..........
==================
DOES IT MEANS , now Fedora users have to build by themselves the Ferefox_52.0esr from source on: https://ftp.mozilla.org/pub/firefox/releases/52.0esr/

OR IS THERE ANY PLAN to provide the two packages: with or without ESR ?

OK I found an other solution here, on fedora french forum:
https://forums.fedora-fr.org/viewtopic.php?id=66354
The last suggestion of 

dannyleconte   11/03/2017 23:37:54
is to use Firefox 52 from standard Fedora repository , but 
 " to get back access to NPAPI plugin in Firefox 52 (not only for flash plugin but all other plugins using NPAPI) :
in about:config you must add a new boolean parameter :
plugin.load_flash_only
set to false "
=====================
To do so;  right click any where on the option list of "about:config"
and in the popup menu chose: New  -> Boolean value
enter the name: plugin.load_flash_only
and its value:  false

Once this parameter is et, without closing Firefox, open again about:plugins
AND THEN you can see all the NPAPI plugin installed: xine, ...
but over all, for the CISCO CCNA students the mandatory icedtea plugin, to be able to pass some exam requiring PaketTracer lab opened by java applet !

(In reply to Yves L'ECUYER from comment #6)
> OK I found an other solution here, on fedora french forum:
> https://forums.fedora-fr.org/viewtopic.php?id=66354
> The last suggestion of 
> 
> dannyleconte   11/03/2017 23:37:54
> is to use Firefox 52 from standard Fedora repository , but 
>  " to get back access to NPAPI plugin in Firefox 52 (not only for flash
> plugin but all other plugins using NPAPI) :
> in about:config you must add a new boolean parameter :
> plugin.load_flash_only
> set to false "
> =====================
> To do so;  right click any where on the option list of "about:config"
> and in the popup menu chose: New  -> Boolean value
> enter the name: plugin.load_flash_only
> and its value:  false

That option may be removed in some future FF release but you can use that now.

If you want to use NPAPI plugins Fedora you also may download FF 52 ESR binary from mozilla.com (https://www.mozilla.org/en-US/firefox/organizations/all/) unpack the tar somewhere and run it.

When the browser is launched it register itself as a default browser and also updates automatically when new update is available.

Note that the recent ESR line (Firefox 52) is going to be dropped by Mozilla by end of this year.

You also have possibility to use old/deprecated browser (like the ESR52 in future) just for the NPAPI plugins...but that's on your own risk as those old browsers may have various flaws/vulnerabilities.