The new update to Google Meet is intended to make it easier for you to identify and deal with the source of echoing audio if Meet is unable to automatically prevent it. In the event that Google Meet’s own audio control functions aren’t up to the task, it will notify the culprit directly.
Echos during video calls are usually caused by your device's speakers projecting audio loud enough for your microphone to catch it. Essentially, your system is picking up its own audio and then re-broadcasting it, creating the feedback. While it's not particularly difficult to fix audio echoes, it can be tricky to pinpoint their source.