Comment 4 for bug 1656695

You're absolutely right that there is room for improvement and this is actually on the todo-list, see [1] for the relevant code section and the list of attributes Scour currently moves to a parent group.

The reason that they're not added yet, is that all of those attributes are pretty "non-standard" and virtually unused:
- "color" (altough it looks obvious) is not used to determine the color of an element - "fill" and "stroke" are! Only if one of those specifies the indirect value "currentColor" the value of the "color" attribute might be used (I doubt many renderers support this and I don't know of an editor which makes use of this)
- "solid-color" is an SVG 2 attribute. It's not yet standardized and not yet supported by Scour
- The style attributes "isolation" and "mix-blend-mode" are part of the yet to be released "Compositing and blending Level 1" CSS extension.
- "color-rendering" and "image-rendering" are the only ones of practical use at this time and even here I wouldn't know which renderer makes use of them and which editor can produce them.

May I ask what software you used to produce this file?

[1] https://github.com/scour-project/scour/blob/210c5f64abdf336e25c58ca927093b3aa94c0a0c/scour/scour.py#L1076