Hello.
Firefox Desktop Browser 73 was released on the 11th Feb.
Firefox release schedules
Firefox release calendar
https://wiki.mozilla.org/Release_Management/Calendar
Firefox 73
Mozilla provides two release notes. One is for users and the other is for developers.
Firefox 73 release note
https://www.mozilla.org/en-US/firefox/73.0/releasenotes/
A page zoom preference was addes. W can set a default zoom rate for reading every web page with offered zoom rate. And it is improved to read web pages with background images in High Contrast Mode on Windows 10.
Firefox 73 release note for developers
https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/73
The release note for developers lists news and changes on APIs or developer tools that may be used by web contents developers or firefox plugin developes.
You can get overview of the new release changes and prepare to manage influence on WebClass functions or your learning materials.
Pickup for webclass
I think there is nothing special to do for using WebClass with new firefox.