Greg Netsas

...this needs a rebase and some conflicts resolution.

Bumped into this again while working on #6578, where the page title for `admin/structure/file-types/add` is "File types" instead of "Add file type" 👎🏼 ...and is showing the horizontal tabs 👎🏼...

> ...and is showing the horizontal tabs 👎🏼 : That is intentional after all - I just thought that it was random because I couldn't figure out the logic. So...

OK, PR ready for review: https://github.com/backdrop/backdrop/pull/4770

@kiamlaluno indeed, but with a caveat: the limitations you are linking to apply to the XML specs - for HTML specs, these apply instead: https://www.w3.org/TR/2012/WD-html-markup-20120329/syntax.html#syntax-attributes ...as stated there: > **Attribute...

...I should also note that our current regex (`'/^([-a-zA-Z]+)/'`) also allows for one or many dashes as attribute names. So you can currently have `-`. `--`, `---` etc. 🤷🏼 ...the...

> ... if the regular expression is going to be changed, it should be changed to allow what HTML allows, so there will not be any further issue we could...

OK, here's an initial PR: https://github.com/backdrop/backdrop/pull/4805 - crossports the D7 https://www.drupal.org/project/drupal/issues/2847553 / https://git.drupalcode.org/project/drupal/-/commit/6b7e2b1ae48bfbad052085bd7a335751b8310cdb (which in turn is a backport of the D8 https://www.drupal.org/project/drupal/issues/2609928 / https://www.drupal.org/commitlog/commit/2/3e28af5d77c901f39ce6568d7f0ccfa90b63b94c) - removes the dash from...

Thanks @kiamlaluno for pointing that out and @herbdool for removing the periods. I have my doubts about that, but in order to not derail this issue here, I've started a...

> - allows underscore as the first character (but not elsewhere, also as per https://www.w3.org/TR/REC-xml/#NT-Name), which is being discussed in https://www.drupal.org/project/drupal/issues/2844627 In https://www.drupal.org/project/drupal/issues/2844627 someone mentioned the XML vs XHTML/HTML standards,...