What is manifest v3?
Manifest V3 is the upcoming version of the manifest file format used by Google Chrome extensions. The manifest file is a JSON file that contains information about the extension, such as its name, version, permissions, and background scripts.

Manifest V3 includes changes to the extension architecture and API that aim to improve extension security, privacy, and performance. Some of the changes include limiting the access of extensions to sensitive user data, such as browsing history, and introducing new APIs for accessing certain functionalities, such as the network and cookies.

One of the most controversial changes in Manifest V3 is the deprecation of the chrome.runtime.sendMessage() method for communication between content scripts and background scripts. Instead, a new messaging system called message passing with port will be introduced. This has raised concerns among developers who rely on chrome.runtime.sendMessage() for various extension functionalities.

Manifest V3 is currently in development and is expected to be released in the near future. Its release has been delayed several times due to concerns and feedback from developers.