I've got a bunch of file level properties that I'd like to be able to export as header meta tags in HTML. So if I've got

#+TITLE: Testing
#+DESCRIPTION: Testing 1 2 3

I could actually get output like
<head>
...
<meta name="title" content="Testing" />
<meta name="description" content="Testing 1 2 3" />
...
</head>

And so on. The org-html-head and org-html-head-extra variables exist to be able to do this project wide for publishing, but they expect stringp, not a function that can be run per file. Is there a decent way to do this that doesn't involve adding #+HTML_HEAD_EXTRA blocks to the files? I suppose I could chain a publishing function in to add what I need before going to HTML, but that seems a like a heavyweight option. Honestly, something like org-html-preamble-format would be nice, but that may not be a great API addition since it's weirdly specific.