When you click “Apply Furigana,” the extension sends only the visible Japanese text from the current tab to the EZFurigana service to generate readings. This data is used solely to fulfill the request and is not retained after processing. No browsing history, account data, or personal identifiers are collected. Settings are stored in browser storage, and optional vocabulary entries are stored locally on your device. See https://www.ezfurigana.com/privacy for more details.