Firefox 102 for developers

This article provides information about the changes in Firefox 102 that will affect developers. Firefox 102 was released on June 28, 2022.

Changes for web developers


No notable changes.


The update media feature that can be used to query the ability of the output device to modify the appearance of content after it is rendered is now available by default (Firefox bug 1422312).


No notable changes.



  • Support of the wasm-unsafe-eval CSP policy directive has been implemented. A document with a CSP that restricts scripts will no longer load and execute WebAssembly unless the CSP uses 'wasm-unsafe-eval' or the existing 'unsafe-eval' keyword (Firefox bug 1740263).


WebDriver conformance

WebDriver BiDi


  • Allow marionette to connect to a windowless instance of Firefox (Firefox bug 1726465).
  • Fixed issue where WebDriver:Navigate with a PageLoadStrategy of "none" returns before navigation has started (Firefox bug 1754132).
  • Fixed a potential race condition in WebDriver:SwitchToWindow when switching to a different tab (Firefox bug 1749666).

Changes for add-on developers

  • The scripting API, which provides features to execute script, insert and remove CSS, and manage the registration of content scripts is now available to Manifest V2 extensions (Firefox bug 1766615).
  • With the introduction of support for the 'wasm-unsafe-eval' CSP keyword in Firefox (Firefox bug 1740263), Manifest V3 extensions are now required to specify this keyword in the content_security_policy manifest key to use WebAssembly. For backwards-compatibility, Manifest V2 extensions can still use WebAssembly without the keyword (Firefox bug 1766027).
  • The nonPersistentCookies option of the privacy.websites cookieConfig property has been deprecated (Firefox bug 1754924).

Older versions