Where the unknown-sources switch is on an Android TV
An Android TV or Google TV will only install from the Play Store until one app is given leave to install others. That leave is the "unknown sources" switch, granted per app. Freehit needs none of it, having no TV app and nothing to install; this page is for anyone putting some other app onto the set, because the switch is filed in three different places depending on the model.
1The three places it can be
Open Settings and look under each of these in turn; the first that exists on the set is the right one:
Apps → Security & Restrictions → Unknown sources Device Preferences → Security & Restrictions → Unknown sources Apps → Special app access → Install unknown appsWhichever it is, a list of apps follows. Switch on only the one that will do the installing (the file manager, the downloader, the browser) and leave the rest off.
2The shortcut: the warning's own Settings button
Often the set raises the matter itself, with a message that it is "not allowed to install unknown apps from this source". That message carries a Settings button that lands on the same list as step 1. Switch the app on, press Back, and the install resumes where it stopped.
3When it is nowhere: developer options
The Google TV Streamer, the Chromecast with Google TV and a few branded sets hide the switch until developer options are on. Go to Settings, System (or Device Preferences), About, highlight the last entry, Android TV OS build, and press OK on the remote seven times; a countdown ends in "You are now a developer". Step 1 or 2 then works as on any other set.
Questions
Does the switch weaken the set?
Only to the extent of the one app it is granted to; nothing else gains install rights, and Play Protect carries on checking what gets installed. It can be switched off again once the app in question is on the set.
Does Freehit need this on a Fire TV?
No. A Fire TV opens freehit.st in its Silk browser with nothing installed and nothing paid; the TV page has the steps. Fire TV's own version of this switch, under My Fire TV and then Developer options, is for other apps.