TYPO3 Core

In issue 77048 I suggested to have SVG files encoded in a css file to limit the number of requests and have better compression.

This could also be extended for icons which are registered dynamically, e. g. by extensions, including, but not limited to
- extension logos
- Buttons in the left sidebar

For registration of an icon, a css class name could be submitted optionally. If not given, e.g. a random string or a hash from the file name including the path could be used as a default for the class name.

The resulting css file could be stored somewhere in TYPO3's cache. Which would then be a static file for web servers again.

Note that it is much easier to extend/recreate such a css file than it would be to create sprites dynamically (which would not work with svg files anyways).

All the advantages I mentioned for 77048 would apply for dynamically registered icons as well. As long as the markup of Icon::render() is used, this could even come along transparently, without a breaking change.