w3C html spec compliance: custom attributes need a data- prefix.

[Kainkainkain]

According to W3C specification, custom attributes should begin with "data-". This is part of HTML5 specification designed to allow web developers to use custom attributes where there's no existing attribute they could use. This helps in semantics, accessibility, etc., while also maintaining validity of the HTML document.

The attribute name should not contain any uppercase letters, and must be at least one character long after the prefix "data-". The attribute value can be any string.

Without the "data-" prefix, the HTML document would be considered invalid in HTML5 Doctype.

https://www.w3.org/TR/2011/WD-html5-20110525/elements.html#embedding-custom-non-visible-data-with-the-data-attributes

Some clients, such as government, have a w3c compliance rules.
Also my linter doesnt like it.

if xyz attribute was simply updated to data-xyz it would be compliant.

I may be wrong, please correct me if anyone knows differing / newer specs.

[jtag05]

Also my linter doesnt like it.

How I got here 😂
I fully support your points otherwise, too lol