With this extension (support English, French, German, Chinese, Japanese, Russian, and more) you can:
1) ADD NEW HTTP HEADER on one http(s) request
2) OVERWRITE HTTP HEADER on one http(s) request
3) specify different http header rules to different request urls
4) Easily turn rules on or off
Wildcard (*) doesn’t appear to be working properly here. RegEx matching would’ve been much better though.