Web Activities (Google Chrome app from Microsoft)

[Sarkar]

Extension Download Link (For more details click the above link)

Google Chrome: Windows Timeline Support
Firefox: Windows Timeline Support – Add-ons for Firefox

It seems MSFT official Timeline extension is available now on chrome store
Web Activities

Update : Yep, it's the official extension and integrate well with windows timeline

 

[Bapun]

See your browsing activities across all your devices in surfaces like Windows timeline and Microsoft Launcher for Android.

With this extension, your browsing history will appear across all your devices in surfaces such as in Windows timeline and Microsoft Launcher for Android. Just sign in with your Microsoft account, select a site you’ve recently visited, and pick up where you left off.