The SVG <filter> element is used to define custom filter effects that can then be referenced by id. The <filter>'s <feColorMatrix> primitive hueRotate type provides the same effect. Given the following:
<svg
xmlns="http://www.w3.org/2000/svg"
viewBox="0 0 220 220"
color-interpolation-filters="sRGB"
height="220"
width="220">
<filter id="hue-rotate">
<feColorMatrix type="hueRotate" values="90" />
</filter>
</svg>
These values produce the same results:
filter: hue-rotate(90deg); /* 90deg rotation */
filter: url(#hue-rotate); /* with embedded SVG */
filter: url(folder/fileName.svg#hue-rotate); /* external svg filter definition */
This example shows three images: the image with a hue-rotate() filter function applied, the image with an equivalent url() filter applied, and the original images for comparison: