By default, the extension does not send any text to another computer on the internet. If the web service has been enabled in the settings of the add-on, the text which is supposed to be checked is sent to https://languagetool.org:8081/
in case connecting with a locally running LanguageTool server was not successful, or this server returned an error. The text transmitted to https://languagetool.org:8081/
is not stored permanently. The connection with https://languagetool.org:8081/
uses a high-grade encryption (TLS-ECDHE-RSA-WITH-AES-128-CBC-SHA, 128 bit keys) to prevent eavesdropping. Therefore, it is very difficult for unauthorized people to read the text while it is traveling across the internet.