From Reddit: The "猫抓 / Cat-Catch" extension can be used, but there is no official English documentation, so you might not know how to use it, and it also requires some knowledge about videos. Fansly videos use two playback technologies: DASH and HLS. For DASH, Cat-Catch will find a file named xxx.mpd, followed by media-video-xxx.mp4 and media-audio-und-xxx.mp4 files, which are the video and audio files, respectively. You just need to select one video and one audio file in Cat-Catch, and a merge button will appear. Cat-Catch can handle the merging perfectly for you. If it's an xxx.m3u8 file, it indicates the video uses HLS technology, and you need to click the magnifying glass icon next to the file, then click "Merge Download."
