I got the LibreOffice plugin from here, but it’s working out-of-the-box and I don’t understand how.
Where is the server?
Is it using LanguageTool remote cloud server?
If so, shouldn’t this be clearly specified in the webpage, like it’s specified for the Thunderbird plugin.
Your privacy is important to us: By default, this extension will check your text by sending it to https://languagetool.org over a securely encrypted connection. No account is needed to use this extension. We don’t store your IP address. See Privacy Policy - LanguageTool for our privacy policy.
Local server: You can set up a local server as described at LanguageTool embedded HTTP Server | dev.languagetool.org (requires Java). Once it’s running, visit the add-on settings and point it to localhost under “Experimental settings”.