my list of cool features:

Gradually rolling out in Fx119, Firefox now allows you to edit PDFs by adding images and alt text, in addition to text and drawings.

If you're migrating your data from Chrome, Firefox now offers the ability to import some of your extensions as well.

As part of Total Cookie Protection, Firefox now supports the partitioning of Blob URLs, this mitigates a potential tracking vector that third-party agents could use to track an individual.

The visibility of fonts to websites has been restricted to system fonts and language pack fonts in Enhanced Tracking Protection strict mode to mitigate font fingerprinting.

Encrypted Client Hello (ECH) is now available to Firefox users, delivering a more private browsing experience. ECH extends the encryption used in TLS connections to cover more of the handshake and better protect sensitive fields.

Firefox is now available in the Santali (sat) language.

Several enhancements have been made to the Inactive CSS styles feature. This feature assists in identifying CSS properties that have no effect on an element. Pseudo-elements such as ::first-letter, ::cue, and ::placeholder are now fully supported.

The JSON viewer is particularly useful for debugging REST APIs, as it displays formatted JSON responses. Now, if the JSON is invalid or broken, it automatically switches to a raw data view, improving the user experience.

Grouping of items in an array (and iterables) is now easier by using the methods Object.groupBy or Map.groupBy.