Font Family Name to set up @font-face

[RosaWagner]

I don't know much in web development so my question may be stupid. Does the font family name of the Variable Font has to be the full font name (ID4)?

Example:
font-family: "Fontname VAR Regular";

It creates weird CSS style stuff when another style from the origin is called.

.fontname-var-regular-light {
    font-variation-settings: "wght" 300;
}

And it is even more counter-intuitive if the origin of the VF is another one than Regular. I would see better name ID 16 (or ID 1 as a fallback) for the font-family entry.