I found this when looking through the code. It's used in the following areas:

Player Death.
Player places a piece in the world.
Player gets a recipe.
Player earns a skill point.
Player has a status applied to them.
Player turns on cheats.
Player gives feedback to the devs directly.
Player opens or closes the inventory menu.
Player crafted an item.
Player opens the Skills/Text/Trophies/Variation menu.
Player enters the main menu.
Player opens the settings menu.
Player quits the game.
Player clicks the logout button.
Player buys or sells an item.
Player starts the game. (Sends game version, Steam ID)
Player starts a game.
Player creates a new world.
Player starts the new world.
Player enters/exists the character selection menu.
Player joins a game or server.
Player enters/exits the credits screen.
Game is awoken from sleep. (ALT+TAB'd?)
Player talks to the Raven.
A ship is destroyed.
A Vegvisir is interacted with. (The location is also sent)
The game crashes.

None of this seems bad at face value, but they haven't disclosed they do this. If you want, you can hook the GoogleAnalyticsV4:LogEvent function and replace the first opcode with RET so you don't emit any analytics, or you can use dnSpy to rewrite the LogEvent function to do nothing, the DLL is called assembly_googleanalytics.dll. There's functions exposed by the Google API itself to allow users to opt out, but none of it is implemented by Valheim itself. The tracker ID is GbOCSs. They are also not using Anonymize IP, which you can't even set, they've put some kind of protection on it. I had to manually pull the value just to even see it with Cheat Engine. If you try to access anonymizeIP you get an access exception, and even if I use reflection, it gets an access exception.