Mozilla announced about The beginning of the implementation testing in Firefox of the third version of the Chrome manifesto, which determines the capabilities and resources available for additions written using the API Webextensions. To test the third version of the manifesto in the beta version of Firefox 101 on the ABOUT page: config
Starting with version 57 Firefox, completely switched to using the API WebexTensions to develop additions and stopped supporting Xul technology. The transition to Webextensions made it possible to unify the development of additions with Chrome, Opera, Safari and Edge platforms, simplified porting the additions between various web browsers and made it possible to fully use the multi-percept mode of operation (recovers of WebExTens can be performed in separate processes, isolated from the remaining parts of the browses). To unify the development of additions with other browsers in Firefox, almost complete compatibility is ensured with the second version of the Chrome manifest.
Currently, the Chrome has been working to switch to the third version of the manifesto, and support for the second version will be discontinued in January 2023. Since the third version of the manifesto has become an object of criticism and will lead to a violation of the work of many additions to block unwanted content and ensure security, Mozilla decided to move away from the practice of ensuring full compatibility with the manifesto in Firefox and implement some changes in other changes.
The main dissatisfaction with the third version of the manifesto is associated with the transfer of the API webrequest one that allowed their own handlers with complete handlers. Access to network requests and capable of modify traffic on the fly. The specified API is used in Ublock Origin and many other additions to block unwanted content and security. Instead of the Webrequest API, the third version of the manifest is proposed to the API declaativeNetrequest . locks that do not allow the use of its own filtration algorithms and does not allow you to set complex rules that overlap each other depending on the conditions.