Update: Updated gtk theme and added gitignore.

usr/share/themes/gtk-dark-keyitdev/metacity-1/titlebuttons/titlebutton-maximize.svg

@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   width="16"
+   height="16"
+   version="1.1"
+   id="svg6"
+   sodipodi:docname="titlebutton-maximize.svg"
+   inkscape:version="1.1.2 (0a00cf5339, 2022-02-04, custom)"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:svg="http://www.w3.org/2000/svg">
+  <defs
+     id="defs10" />
+  <sodipodi:namedview
+     id="namedview8"
+     pagecolor="#505050"
+     bordercolor="#eeeeee"
+     borderopacity="1"
+     inkscape:pageshadow="0"
+     inkscape:pageopacity="0"
+     inkscape:pagecheckerboard="0"
+     showgrid="false"
+     inkscape:zoom="43.375"
+     inkscape:cx="8"
+     inkscape:cy="8"
+     inkscape:window-width="1920"
+     inkscape:window-height="1014"
+     inkscape:window-x="0"
+     inkscape:window-y="0"
+     inkscape:window-maximized="1"
+     inkscape:current-layer="svg6" />
+  <rect
+     y="6.1035e-7"
+     width="16"
+     height="16"
+     ry="1.6931e-5"
+     opacity="0"
+     stroke-width=".47432"
+     style="paint-order:markers stroke fill"
+     id="rect2" />
+  <path
+     d="m8 15c3.8659 0 6.9999-3.134 6.9999-7s-3.134-7-6.9999-7c-3.866 0-7.0001 3.134-7.0001 7s3.134 7 7.0001 7"
+     fill="#59c837"
+     fill-rule="evenodd"
+     id="path4"
+     style="fill:#9ece6a;fill-opacity:1" />
+</svg>