"Some attributes are required to be followed by ..."

[Zectbumo]

https://html.spec.whatwg.org/multipage/syntax.html#start-tags:space-characters-3

Some attributes are required to be followed by a space.

I can't find any evidence of this being true in the referenced spec following the selected text. What attributes would require to be followed by a space??

[domenic]

I agree, this doesn't seem correct. The only thing I can think of is if it's saying something like <img src=https://example.com/foo/> is bad and <img src=https://example.com/foo /> is OK. But point 6 already kind of covers that.

@zcorpan has a good history of remembering or grokking what this kind of old spec text means, so let's see if he has any ideas. Otherwise, we should remove this.

[zcorpan]

Empty attribute syntax
If an attribute using the empty attribute syntax is to be followed by another attribute, then there must be ASCII whitespace separating the two.

Unquoted, single-quoted and double-quoted also need a space if followed by another attribute.

Unquoted attribute value syntax
If an attribute using the unquoted attribute syntax is to be followed by another attribute or by the optional U+002F SOLIDUS character (/) allowed in step 6 of the start tag syntax above, then there must be ASCII whitespace separating the two.

Example:

<br class=foo />

(removing the space makes the slash part of the attribute value)

The text in step 6 of start tag is not a "must" requirement.