From mozilla
The <feColorMatrix> SVG filter element changes colors based on a transformation matrix. Every pixel's color value
\([R,G,B,A]\) is matrix multiplied by a \(5\times 5\) color matrix to create new color \([R',G',B',A']\).
\[\\begin{bmatrix}R'\\\\G'\\\\B'\\\\A'\\\\1\\end{bmatrix}= \\begin{bmatrix} r_1 & r_2 & r_3 & r_4 & r_5 \\\\ g_1 & g_2 & g_3 & g_4 & g_5 \\\\ b_1 & b_2 & b_3 & b_4 & b_5 \\\\ a_1 & a_2 & a_3 & a_4 & a_5 \\\\ 0 & 0 & 0 & 0 & 0 \\end{bmatrix}\\cdot\\begin{bmatrix} R \\\\ G \\\\ B \\\\ A \\\\ 1 \\end{bmatrix} \]