SVG Documentation on MDN: What It Covers and How It Applies to SVG Favicons
What MDN's SVG documentation is, what it covers, and how to use it to check SVG favicon and logo files for real vector artwork, structure and browser support.
Contents
The short answer
MDN Web Docs, the developer documentation maintained by Mozilla and its contributors, has a reference section on SVG (Scalable Vector Graphics). It is a technical reference for the format: what elements and attributes exist, how they behave, and how browsers support them. It is not a logo library, a download source, or a design tool. If you are preparing an SVG favicon or a vector logo file, MDN is where you check whether the markup in that file is valid and will behave as you expect in a browser.
The searches for MDN's SVG pages, whether in English or in Russian as "Документация SVG на MDN", lead to the same resource. MDN publishes much of its content in several languages, but how complete and current a given translation is was not confirmed in the material behind this article. When a translated page and the English page disagree, the English reference is usually the one that is updated first.
What the SVG reference covers
The SVG section of MDN is generally organized into a few kinds of material:
- Element reference: one entry per SVG element, such as svg, path, circle, rect, g, defs, use, style and image, with the attributes each element accepts.
- Attribute reference: entries for attributes such as viewBox, fill, stroke, transform and d, the attribute that holds path drawing commands.
- Tutorials and guides: introductory explanations of coordinate systems, paths, fills and strokes, gradients, and text.
- Browser compatibility tables: on many reference entries, a table showing which browsers support the feature and any known limitations.
For favicon work, the relevant material is spread across two areas. The SVG reference explains what goes inside the icon file. The HTML reference, especially the entry for the link element and its rel="icon" value, explains how a page points to that file. The MIME type for SVG is image/svg+xml, and that is the value used in the link element's type attribute when declaring an SVG icon.
How MDN differs from other SVG resources
| Resource type | Main purpose | What it tells you about a logo or favicon file |
| MDN SVG reference | Explains SVG elements, attributes and browser behavior for developers | Whether the markup is meaningful and supported; does not judge design quality |
| W3C SVG specification | The formal standard that defines the format | The authoritative rules; denser and less practical for everyday checking |
| Vector editors (for example Illustrator, Inkscape, Figma) | Create and export artwork | Produce the file; export settings decide how clean or bloated the markup is |
| Logo download or icon sites | Distribute finished files | Supply files whose structure and licensing still have to be checked |
In short, MDN sits between the formal specification and the design tool. It is the practical place to look up what a specific tag or attribute in an exported file actually does.
Using MDN to check whether an SVG is really vector artwork
An .svg extension does not prove that a file contains editable vector paths. SVG is a container format: it can hold shapes drawn with path, circle, polygon and similar elements, and it can also embed a bitmap through the image element, often as base64-encoded PNG or JPEG data placed directly in the file. A file built that way opens like an SVG, but the logo inside is still a raster image and will blur or pixelate when scaled.
MDN's element entries help you read a file's source and tell these cases apart:
- Mostly path, rect, circle, polygon and g elements with fill and stroke values: the artwork is drawn as vectors.
- An image element whose href holds a long run of encoded data or points to a .png or .jpg file: the visible artwork is an embedded raster, not vector paths.
- A mix of both: some parts scale cleanly and others do not, which is common when a traced or pasted bitmap was left inside an otherwise vector file.
- Text kept as text elements rather than converted to outlines: the result depends on the viewer having the right font, which matters for logo delivery.
Vector paths are also not the same thing as well-structured, editable artwork. A file can be fully vector and still be hard to work with: shapes may be flattened into one path, layers may be ungrouped, or the markup may be cluttered with editor metadata. MDN explains what the elements mean, but judging whether the structure suits a particular editing task is an editorial call.
Details that matter for SVG favicons
A few SVG concepts documented on MDN directly affect how a favicon behaves:
- viewBox: defines the internal coordinate system, so the icon scales to whatever size the browser draws it at. A square viewBox suits favicons, since they are shown in square slots.
- Embedded style element: an SVG can carry its own CSS, including media queries such as prefers-color-scheme. Designers use this to switch icon colors between light and dark browser themes from a single file.
- Simplicity at small sizes: SVG scales without losing sharpness, but fine detail in a full logo can still turn to mush at very small favicon sizes. That is a design limit, not a format limit, and is why simplified marks are often used as favicons.
- Browser support: MDN's compatibility tables are the place to confirm whether SVG icons, and features such as media queries inside them, work in the browsers you care about. Many sites also keep a raster fallback, such as a PNG or ICO icon, for browsers or contexts that do not use the SVG.
Current browser support figures for SVG favicons were not available in the material behind this article. Check the live compatibility data on MDN rather than relying on a summary that may be out of date.
What MDN does not answer: permissions and trademarks
MDN documents the SVG format. It says nothing about whether you may use a particular logo. Being able to download a logo file, even a clean vector one, is separate from having permission to modify it, to use the fonts it was built with, or to display the brand's trademark. Those questions depend on the logo owner's brand guidelines, the font license, and trademark law, and should be checked with the rights holder before you edit or reuse artwork that is not yours.
Gaps in this overview
This article is based on general, verifiable knowledge of the SVG format and of what MDN publishes. It does not confirm the current page structure, update dates, completeness of translations, or specific browser-support figures, because no direct evidence on those points was available. For those details, the live MDN pages are the reference to rely on.