The ascent attribute defines the maximum unaccented height of the font within the font coordinate system.

The azimuth attribute specifies the direction angle for the light source on the XY plane (clockwise), in degrees from the x axis.

The edgeMode attribute determines how to extend the input image as necessary with color values so that the matrix operations can be applied when the kernel is positioned at or near the edge of the input image.

The color-interpolation-filters attribute specifies the color space for imaging operations performed via filter effects.

The data-* SVG attributes are called custom data attributes. They let SVG markup and its resulting DOM share information that standard attributes can't, usually for scripting purposes. Their custom data are available via the SVGElement interface of the element the attributes belong to, with the SVGElement.dataset property.

The flood-opacity attribute indicates the opacity value to use across the current filter primitive subregion.

The calcMode attribute specifies the interpolation mode for the animation.

The <hkern> SVG element allows to fine-tweak the horizontal distance between two glyphs. This process is known as kerning.

The k4 attribute defines one of the values to be used within the arithmetic operation of the <feComposite> filter primitive.

The horiz-origin-x attribute indicates the x-coordinate in the font coordinate system of the origin of a glyph to be used when drawing horizontally oriented text.