When mixing Japanese and Western text, and the Western text contains multiple words (and thus, at least an internal ASCII space), like:
これはW3C jlreq-dドキュメントです。
In this sentence, ‘W3C jlreq-d’ should be read and perceived as a single conceptual block. If the CJK-Latin extra spacing (e.g., 1/8-em) is smaller than the internal ASCII space between ‘W3C’ and ‘jlreq-d’, could it visually break the phrase? This might cause the sentence to be misread as two separate entities: ‘[これはW3C]’ and ‘[jlreq-dドキュメント]’.
Given this conflict, is it necessary for jlreq-d to mention the spacing and the different amounts of extra spacing specifically?
See also w3c/clreq#717