Many streaming services (like TV broadcasters’ apps) allow downloads for offline viewing within their mobile apps (iOS/Android). TheoPlayer is often embedded inside these apps.
Downloading video from THEOplayer without permission is if: how to download video from theoplayer
There are several browser extensions designed to sniff out video streams. Since THEOplayer often uses HLS (m3u8) or DASH (mpd) protocols, you need an extension capable of handling those. Many streaming services (like TV broadcasters’ apps) allow