You can find the RSS feed (Subscribe) button in the toolbar palette in the "View > Toolbars > Customize" window and drag the button on a toolbar.
Open the Customize window via "View > Toolbars > Customize" or via "Firefox > Options > Toolbar Layout"

• http://kb.mozillazine.org/Toolbar_customization
• https://support.mozilla.com/kb/Back+and+forward+or+other+toolbar+items+are+missing

• RSS Icon: https://addons.mozilla.org/firefox/addon/rss-icon/
• RSS Icon In Awesombar: https://addons.mozilla.org/firefox/addon/rss-icon-in-awesombar/

So where do you find "View"?

This latest version of Firefox is a shamblesand raises major questions over the quality of open source software with its unnecessary changes for the sake of change and facilities being "acciderntally" knocked out. It begins to make the worst of IE look good!

Press F10 or tap the Alt key to bring up the "Menu Bar" temporarily if the Menu Bar is hidden.

Why do we now need to install an plugin for this ? The RSS icon in the address bar made sense and people where used to it.

Now the default icon clutters up FF and is never where I need it. People are wasting time looking for it, then searching the Internet for "why what where" and then installing extra addons.... .. .