We have noticed that EB (5.1.15) generates HTML content with repeated HTML ID attribute values of "eb". Although, standard browsers display this pretty much as intended, the issue comes for HTML validation, which tends to cause issues for accessibility and "browsers" (user agents) that are more strict about HTML conformance - as is the case for screen readers and similar accessibility aids. It is my understanding that IDs are to be unique to the whole document (see https://stackoverflow.com/questions/9454645/does-id-have-to-be-unique-in-the-whole-page - it has handy references to the relevant HTML 4 and HTML 5 sections)

At present, EB generates a wrapping DIV with id="eb" and then within that DIV, the wireframe template generates a image popup DIV also with id="eb" (and class="eb-image-popup"). I can, of course, change the wireframe code to use a different ID value, but at the next update this will be overwritten.

I haven't checked exhaustively, but the theme CSS file does reference #eb over 3000 times, and #eb.eb-image-popup 8 times - the latter one could relatively safely be rewritten as either #<newid>.eb-image-popup or #eb .eb-image-popup - but, as I say, I haven't exhaustively checked other EB CSS files.

This does seem rather "trivial" by most measures, but, unfortunately, it makes the task of improving accessibility much harder, and as that is gradually becoming a source of litigation in many jurisdictions (US, CA and the EU to name a few), it should be addressed by all of us.