Configuration form page (/admin/structure/ultimenu) drupalSettings data is missing.

I don't know what's causing it, maybe it's just a bug unique to my site

Thank you.

Is it about HTML < problem, or drupalSettings data missing?
If the first, understood, and it likely happens at multilingual site. Your patch should be in.
If the latter, please clarify. Try switching admin theme, or your own to core ones.

Thank you for your reply.
But as far as I know，In Drupal, the t() function is used to translate strings and supports HTML markup. However, if you use the '<' character in the string, it can cause problems because this character may be interpreted as the start of an HTML tag. This can affect JavaScript on the page, resulting in missing content in drupalSettings and other issues.

Committed. Thank you for contribution and patience.

Automatically closed - issue fixed for 2 weeks with no activity.