Should aggregated CSS and JS declare utf-8 in Content-Type header?

Problem/Motivation

For years now I've encountered rare, random issues where stylesheets are seemingly being loaded with incorrect encoding. This might occur once every few weeks, and only for one page view. None of the usual suspects really apply here like lack of <meta charset="utf-8"> in the document, etc...

That led me to start grasping at straws and I did an AI query on this which led to the tool citing https://issues.chromium.org/issues/40302205 (disk cache nondeterminism).

I looked up the implementation of Drupal's asset aggregator controller and sure enough, the Content-Type header lacks encoding.

Should the Content-Type response header be updated to text/{css|javascript}; charset=utf8 for these resources? What about the .htaccess file for such resources?

Steps to reproduce

Add a

.some-selector {
  content: '“';
}

selector, then notice that rarely, randomly the character is printed as “. Do a hard refresh; note that the character is printed properly (interpreted as utf-8).

Proposed resolution

Perhaps add an explicit charset to the CSS and JS Content-Type headers?

Remaining tasks

TBD

User interface changes

None

Introduced terminology

None

API changes

None

Data model changes

None

Release notes snippet

TBD