2018-12-29 Firefox extensions I can not live without

My current list of Firefox extensions on my Mac is as follows:

And finally to fit things in perfectly, put this bit in your userChrome.css to move the tabbar close button to the left:

    .tabbrowser-tab:not([pinned]) .tab-close-button {
        -moz-box-ordinal-group: 0 !important;
        -moz-margin-start:-4px !important;
        -moz-margin-end:4px !important;

You could use the Shadowfox style for a darker user interface. And furthermore, if you run your OS in dark mode, then Firefox will follow this reasonably well. However as of 2019-09-02 there are still things left to be desired; upon opening a new tab, it sometimes flashes white. To fix this:

  #browser vbox#appcontent tabbrowser, #content, #tabbrowser-tabpanels, 
  browser[type=content-primary],browser[type=content] > html {
      background: #1D1B19 !important

Note that userChrome.css might soon be ignored and you'll need to enable it manually.

Source: https://fedidat.com/640-dark-newtab-firefox/