The page tabs (Comments, Attachments, Information) and other dynamically loaded content fail to load when XWiki is accessed over HTTP/2

Suggested fix :

Sanitize the header value in #sendRequiredSkinExtensions (in display_macros.vm) after #getRequiredSkinExtensions and before $response.setHeader(...).

Keep the newline join inside #getRequiredSkinExtensions (needed for line-by-line filtering / duplicate removal). Only flatten CR/LF for the HTTP wire format: the client injects the value as an HTML fragment, so a space is a valid separator.

Proposed change:
 

#macro (sendRequiredSkinExtensions)
  #getRequiredSkinExtensions($requiredSkinExtensions)
  #set ($requiredSkinExtensions = $requiredSkinExtensions.replaceAll('[\r\n]+', ' ').trim())
  #set ($discard = $response.setHeader('X-XWIKI-HTML-HEAD', $requiredSkinExtensions))
#end