Just found that at least Chrome and Safari of 2016 supported this undocumented value, which is not listed in W3C documents.
Not sure if support is dropped, but Chrome dev mode suggests the 'overlay' value for overflow-y.
Can't find it at the caniuse.com, please add. TY in advance )
I assume you mean the scrollbar-gutter property, correct?
That's another property. Thank you.
What I meant was overflow: overlay. From what I've googled it is only supported by -Webkit browsers, is non-standardized, and allows the content to extend beneath the scrollbar.
From skimming through this csswg draft issue it seems indeed webkit's overflow: overlay was standardized and the property renamed to scrollbar-gutter as defined in CSS overflow module level 4.
Now available at https://caniuse.com/css-overflow-overlay
Most helpful comment
From skimming through this csswg draft issue it seems indeed webkit's
overflow: overlaywas standardized and the property renamed toscrollbar-gutteras defined in CSS overflow module level 4.