In case one needs to download a video from Facebook there are several solutions, and also a consideration (besides from ownership and copyright).

First of all, videos found on Facebook are very often shared from another online source, e.g. YouTube. In order to access the video in the best quality - and as a bonus get background information such as "who, when, and why" - it is recommended to do a search for the original source: Use meaningful search phrases such as video title (if given), topic, named entities (e.g. places, people). Do this in your browser using your preferred search engine, and switch to the "videos" category in the search. It is highly likely to find a promising result from thumbnails, playing time, and title.

If the original video is found, it can be downloaded using Video Download-Helper, or 4K Video Downloader.

If the video cannot be found elsewhere, or if you simply prefer to download it directly without looking for original sources there are several solutions.

The best will solution will usually be by using 4K Video Downloader, which will fetch the video in the best quality avaliable.

You can also edit the video URL in order to get the mobile version which is downloadable, but not in the highest quality (as described in the video tutorial).

The fastest solution for getting the video in a better quality without any applications installed will be from using a third party service, such as fdown.net (recommended in the video tutorial from PCMag), or getfvid.com

(URL www.getfvid.com/), another tried and tested online service.

Paste the Facebook video URL from the share option (see video tutorial if needed) in either service, and use the download button to save the video file locally.

Online services for direct downloads:
fdown.net
getfvid.com