Change Layout of default JSON viewer through Add-On?

Add-ons Development
#1

Hello community,

I’d like to change the layout of the default JSON viewer in Firefox (about:config --> devtools.jsonview.enabled --> true).
Testlink: https://jsonview.com/example.json

I know it’s possible via:

  • Create a userContent.css file (within chrome folder in the profile)
  • Set toolkit.legacyUserProfileCustomizations.stylesheets to true in about:config
  • Restart Firefox

But I’d like to apply CSS changes via an Add-On and to me it looks like that neither content scripts nor user scripts are working when the default JSON viewer is loaded.

Do you have any further information?

Best regards

Daniel

#2

I think the JSON viewer is devtools code, and as such privileged. It being privileged means that you can’t directly interact with it as webextension.

#3

Thanks. That’s not want I want to read but it sounds comprehensible :wink:

#4

Extensions can intercept certain files as they come in, and show them in their own extension pages. It’s been a while since I’ve used it, but I know of at least one RSS reader extension that does that: