missing-glyph: An element used to define the graphics to use when an attempt...
In mslegrand/svgR: svgR is an R DSL to generate svg markup

The missing-glyph's content is rendered, if for a given character the font doesn't define an appropriate <glyph>.

Complementary Attributes: vert.origin.xy
Core Attributes: id, xml.base, xml.lang, xml.space
Presentation Attributes: clip.path, color.interpolation, color.rendering, cursor, enable.background, filter, mask, opacity
Unclassified: class, d, horiz.adv.x, style, vert.adv.y, vert.origin.x, vert.origin.y

Animation Elements: animate, animateColor, animateMotion, animateTransform, set
Descriptive Elements: desc, metadata, title
Gradient Elements: linearGradient, radialGradient
Graphics Referencing Elements: image, use
Non-structural Container Elements: a, marker, mask, pattern, switch
Shape Elements: circle, ellipse, line, path, polygon, polyline, rect
Structural Container Elements: defs, g, svg, symbol
Text Content Elements: text
Uncategorized Elements: altGlyphDef, clipPath, color.profile, cursor, filter, font, font.face, foreignObject, script, style, view