Google-chrome – How to remove a specific request header before sending a request in Chrome or Firefox

HAR is HTTP Archive, and is exactly what you want to save (it includes HTTPS unencrypted).

Luckily this is now a basic feature of all major browser (it was not when you asked the question). No more need of third party extensions.

In Firefox (v41+):

• Start Firefox Developer Tools in Network mode (Top right menu > Developer > Network, or ctrl-shift-Q)
• Reproduce the target scenario
• Save the capture by right-clicking on the grid and choosing "Save all as HAR"
• Export the capture to a HAR file

Other browser:

In recent version of all browser, you can save HAR easily:

https://toolbox.googleapps.com/apps/har_analyzer/

If you are not restricted with Firefox, you can use Google Chrome's extension Header Hacker.

It provides:

1. custom request headers (you're able either add new headers or override existing ones)
2. permanent headers for specified hosts (you're able either add new headers or override existing ones)

So that you can solve your problem with second feature.

I'm using the extension a lot and it works fine for me.