Manifest V3
Also known as: mv3
The current Chrome extension platform, which replaces the webRequest blocking API with declarativeNetRequest.
Manifest V3 is the version of Chrome's extension API that all new extensions must use. Its most controversial change for ad blockers was removing the ability to inspect and cancel network requests with arbitrary JavaScript (webRequest blocking) in favour of declaring rules in advance (declarativeNetRequest).
In practice, modern ad blockers (including NovaBlock) deliver near-identical filtering quality under MV3 by pre-compiling filter lists into declarative rules. The transition has reduced some advanced capabilities but also lowered the permission footprint extensions need to function.