SVG icons currently in extension don't seem to be minified. And they don't get minified by RL.
For example `.mw-ui-icon-notifications:before`
from https://en.m.wikipedia.org/wiki/Main_Page:
> view-source:data:image/svg+xml,<%3Fxml%20version%3D"1.0"%20encoding%3D"UTF-8"%20standalone%3D"no"%3F>%0A<svg%20xmlns%3D"http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg"%20width%3D"48"%20height%3D"48"%20viewBox%3D"-282.375%20419.5%2048%2048"%20enable-background%3D"new%20-282.375%20419.5%2048%2048">%0A%20%20%20%20<path%20d%3D"M-249.122%20464.146h11.915c1.095%200%202.192-.728%202.554-1.703.486-.97.242-2.187-.61-3.04-3.89-4.01-4.74-9.972-5.47-15.683-1.215-8.51-2.553-18.116-14.71-19.334v-1.58c0-1.58-1.214-2.797-2.795-2.797-1.582%200-2.797%201.215-2.797%202.795v1.58c-12.037%201.22-13.375%2010.824-14.59%2019.335-.85%205.712-1.58%2011.673-5.47%2015.682-.73.853-.974%201.947-.608%203.04.486.977%201.458%201.704%202.552%201.704h11.67m9.24%203.405c-1.947%200-3.407-1.46-3.528-3.404h7.05c-.118%201.823-1.702%203.405-3.522%203.405zm0-9h-15.443c2.31-4.496%203.04-9.483%203.65-14.104%201.336-9.847%202.43-14.59%2011.793-14.59%209.484%200%2010.574%204.744%2011.915%2014.59.605%204.62%201.337%209.606%203.646%2014.105h-15.56z"%20id%3D"path4"%20fill%3D"%23555"%2F>%0A<%2Fsvg>%0A