WebDriver is a remote control interface that enables introspection and control of user agents. As such it can help developers to verify that their websites are working and performing well with all major browsers. The protocol is standardized by the W3C and consists of two separate specifications: WebDriver classic (HTTP) and the new WebDriver BiDi (Bi-Directional).

This newsletter gives an overview of the work we’ve done as part of the Firefox 139 release cycle.

Contributions

Firefox is an open source project, and we are always happy to receive external code contributions to our WebDriver implementation. We want to give special thanks to everyone who filed issues, bugs and submitted patches.

In Firefox 139, one contributor managed to land a fix in our codebase:

• Dan (temidayoazeez032) updated the TabManager.getBrowsingContextById() helper method to not return an already closed Browsing Context.

WebDriver code is written in JavaScript, Python, and Rust so any web developer can contribute! Read how to setup the work environment and check the list of mentored issues for Marionette, or the list of mentored JavaScript bugs for WebDriver BiDi. Join our chatroom if you need any help to get started!

General

Bug fixes:

• The priority manager (on macOS, the background QoS manager) in Firefox, which manages IPC message prioritization between the parent and content processes, has been temporarily disabled for all supported Remote Protocols. This change resolves an issue where, under high system load, initial page loads in newly opened background tabs were not being scheduled, resulting in certain commands hanging.

WebDriver BiDi

New: emulation.setGeolocationOverride command

Implemented the emulation.setGeolocationOverride command, allowing tests and automation tools to simulate geographic locations across specified browsing contexts or user contexts. This enables consumers to test location-aware features such as geofencing for local recommendations.