If I use "-webkit-background-clip: text;" in my CSS, the validator reports:
If I then change it to "background-clip: text;", the validator reports:The "-webkit-background-clip" vendor prefixed property is now considered obsolete and/or useless. Today, it is recommended that only the non-prefixed version of this property be used (vendor prefixes are not necessary). It is recommended that this property be removed.
Mozilla claims "background-clip: text;" is a valid property:The value for the CSS3 "background-clip" property is invalid. CSS3 allows this value to be <box>#, where <box> is "border-box", "padding-box", or "content-box". This property determines the background painting area. This property is not valid in CSS 2.1.
https://developer.mozilla.org/en-US/doc ... round-clip
However, programmers on Stackoverflow complain that the non-prefixed version is useless, and caniuse.com claims in the notes section:
See: https://caniuse.com/#search=background-clipFirefox, Chrome and Safari support the unofficial -webkit-background-clip: text (only with prefix)
So...perhaps only validate the -webkit- prefixed version, and issue a warning for the non-prefixed version with helpful notes?