All of these things are optional, meaning that by putting /* before the code, it turns that part off. All snippets here are on by default and are 100% optional.
Brave's close button icon for some reason is more leaned towards the right of the tab. Now initially this was left off as it made it more similar to brave, though after more thought even padding looks much better and also doesn't ruin closing tabs when you have a massive amount of tabs open.
Before
After
/* Makes Close Tab Button Have Even Padding On Right */
/* On By Default */
.tab-close-button {
margin-inline-end: 0px !important;
}
Brave has a more "dont you dare change anything" rule about how it treats it's browser features. So with that ideology, adjusting the size of the URL bar is something that you can't do. This snippet adds extra space to the left and right of the URL bar, but only when the window is maximized. This version was chosen as when brave isn't maximised, the blank space is automatically adjusted, which is what Firefox's Flexible Space does automatically. Now one could just use flexible space and turn this snippet off, though that includes more work for the user so having this on would assume that the user doesn't have any flexible spaces in their toolbar
/* Adds Space To URL Bar Similar To That Of Brave */
/* On By Default */
:root[sizemode="maximized"] #urlbar-container{
margin-right: 120px !important;
margin-left: 120px !important;
}
Firefox decided to have about:newtab (new tabs) have a favicon (little icon on the left of your tab) which displays the icon of the current version of Firefox you are using. Brave doesn't do this, but instead just leaves it blank. This snippet does exactly that; terminates that icon.
/* Terminate New Tab Favicon */
/* On By Default */
.tabbrowser-tab[label^="New Tab"] .tab-icon-image {
display: none;
}