In upcoming Firefox 60, Mozilla has moved Cookies Settings into Site Data section and this change also has removed the ability to manage individual cookies in the preferences.
Cookie Settings moved to Site data section in Firefox 60
In current Firefox 58.0.2 and earlier versions, you can able to delete cookies for a site or all cookies stored on your computer by visiting options > Privacy & Security > History section (either if you choose Firefox will ‘remember history’ or ‘use Custom settings for history’).
Or you can also clear Firefox cookies by bringing up ‘clear recent history’ dialog. Let me remind you Firefox offers Forget button to clear your recent history .
Till now if you’ve deleted all cookies in Firefox, but not the individual cookies by opening Cookies dialog, the change made in Firefox 60 won’t bother you too much.
This Cookies dialog window has been removed
In version 60, the Firefox team has merged Cookie Settings into Site Data section, as a result the new section becomes Cookies and Site Data.
By using ‘Settings’ dialog in the new section, you can able to delete both cookies and site data, but not the cookies.
But still, by using Page info dialog (are you missing about:permissions page?) or devtools, you can able to delete individual cookies in Firefox from version 60 or later, here is how that can be done.
Clearing individual cookies in Firefox from version 60
I. 1. Click on 
button in the left of URL bar to open control center,
2. Click on ‘>’ and select ‘More information’
3. Click on ‘View Cookies’
II. For more granular control on cookies, you better visit Developer tools.
Press Ctrl+Shift+I, click on ‘Storage’ and select Cookies,
ICYDK, the Firefox version 60, offers a new preference to open search results in address bar in a new tab.
READ: Firefox 60: Always Open address bar results in a new tab
Also see: How to block Third-Party Cookies in Chrome, Firefox and IE Browsers
