Kiku Hours keeps everything it records in your browser. There is no account and no server of ours that holds your data.

Audio: to detect the language of a video, the extension holds the most recent minute of the video's audio in memory and analyses it in windows of up to thirty seconds, entirely on your computer, with a language-identification model that ships inside the extension. No audio leaves your machine, nothing is recorded or stored, and only the resulting language label is kept. On YouTube it also reads the language of the video's auto-generated captions from the video's own page. On Netflix no audio is analysed; the language comes from the audio track you selected.

Usage analytics: a small number of anonymous usage events (installed, a language was detected, a feature was used) are sent to PostHog, hosted in the EU, to see whether the extension works. Each install is identified by a random id; no name, email or account exists. Never sent: video ids, titles, URLs, the language of any video, durations or totals. The languages you declare as native or learning are included as codes when you declare them. IP addresses are discarded on receipt and no location is derived. In Firefox this collection is controlled by the data-collection permission shown at install.

Your data: export it as a spreadsheet, back it up to a file, restore it elsewhere, or delete it, from the extension's Settings. Removing the extension deletes it.

Full policy: https://kikuhours.com/privacy