Vague svg support warning

[mattgarrish]

Section

https://www.w3.org/TR/epub-34/#sec-svg

Describe the problem

The SVG Content Documents section begins with this warning:

Reading systems may not support all the features of [svg] or support them across all platforms that reading systems run on. When utilizing such features, EPUB creators should consider the inherent risks on interoperability and document longevity.

When utilizing what features? We're so vague this kind of warning could be applied to almost every technology in epub.

Describe the fix or new feature you propose

If there are specific features we want to warn people about, even if the list isn't comprehensive ("in particular ..."), let's list them rather than having such an open-ended warning.

If there aren't, can we drop this warning?

[iherman]

The SVG Content Documents section begins with this warning:

Reading systems may not support all the features of [svg] or support them across all platforms that reading systems run on. When utilizing such features, EPUB creators should consider the inherent risks on interoperability and document longevity.

When utilizing what features? We're so vague this kind of warning could be applied to almost every technology in epub.

Indeed: there may be new features coming to HTML that are or are not picked up, at a specific point in time, by the different webviews, ie, RS's.

Describe the fix or new feature you propose

If there are specific features we want to warn people about, even if the list isn't comprehensive ("in particular ..."), let's list them rather than having such an open-ended warning.

If there aren't, can we drop this warning?

Yes, I agree. In some sense, the big "caution" box in §1.3 Relationship to other specifications covers the SVG as well. Maybe we can consider adding the general term "should consider the inherent risk..." to that text, but I am not sure if it is worth the trouble.

(B.t.w., the caniuse for SVG refers to SVG 1.1, the latest official version is SVG 1.2... there is a mess on that front anyway. We should not try to be in sync with that...)

[mattgarrish]

Indeed: there may be new features coming to HTML that are or are not picked up

Ya, it's kind of a fill-in-the-blank generic warning. Feature of JS are not supported by all reading systems or on all platforms, so be cautious about using these feature. Features of CSS are not supported by all reading systems or on all platforms, so be cautious about using these features. Features of FXL are not supported by all reading systems or on all platforms, so be cautious about using these features. And so on.

If we said "New features added in SVG2 may not be supported..." at least that would limit what people need to concern themselves with. Otherwise, I don't see the value here.