You get notified of certain errors only checked by having a premium subscription, but it won't tell you where or what the errors are and you can't disable this incredibly annoying behavior. Also, despite the fact that there's no mention of AI in the description, AI integration is all over it (and very limited for free users). Even the name of the extension in the Add-On Manager has AI in it. It's the very first word! What a weird, shady-seeming, and obnoxious extension.
And by the way, LanguageTool, your setup process has at least two typos in it. You can't even be bothered to run your own copy through the AI tools you try to push on us? You failed to inspire confidence from the very beginning and then you lived up to that impression spectacularly.