Why are the -o- and -moz- properties are not added as well?
When I show the generated CSS there is a warning sign on the left that says:
The property -o-transition-timing-function is compatible with -webkit-transition-timing-function and should be included as well.
The property -moz-transition-timing-function is compatible with -webkit-transition-timing-function and should be included as well.
I deliberately left out certain vendor prefixes necessary for older versions of browsers that are in very little use these days. This was based on some research I did when I first implemented the transition properties.
I don’t always agree with the CSS linting that comes with the ACE editor (the editor MT uses for formatting code). I think some of it’s opinions are based on times past. But I’m hesitant to switch it off as it does catch genuine syntax errors in the stylesheet.