Firefox 102 for 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 (bug 1422312).

No notable changes.

• The Non-standard interfaces IDBMutableFile, IDBFileHandle, IDBFileRequest, and the method IDBDatabase.createMutableFile() have been disabled by default in preparation for removal in a future release (bug 1764771).
• Transform streams are now supported, allowing you to pipe from ReadableStream to a WritableStream, executing a transformation on the chunks. The update includes the new interfaces TransformStream and TransformStreamDefaultController and the method ReadableStream.pipeThrough() (bug 1767507).
• Readable byte streams are now supported, allowing efficient zero-byte transfer of data from an underlying byte source to a consumer (bypassing the stream's internal queues). The new interfaces are ReadableStreamBYOBReader, ReadableByteStreamController and ReadableStreamBYOBRequest (bug 1767342).

DOM

• The Firefox-only property Window.sidebar has been moved behind a preference and is planned for removal (bug 1768486).

WebDriver BiDi

• There are some improvements to Webdriver BiDi's browsingContext.navigate
  • Fixed edge cases where the navigation could incorrectly timeout (bug 1766217).
  • Added support for hash changes (bug 1763127).
  • Added support navigation to error pages (bug 1763124).

Marionette

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

• 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 (bug 1766615).
• With the introduction of support for the 'wasm-unsafe-eval' CSP keyword in 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 (bug 1766027).
• The nonPersistentCookies option of the privacy.websites cookieConfig property has been deprecated (bug 1754924).