nico downloader is an unofficial extension that supports saving videos from NicoNico and enhances the usability of the platform. It creates a link to save NicoNico videos directly below the video page title. Additionally, it extends and improves various services on NicoNico, including NicoNico Douga Encyclopedia. These features automate the process of creating links, making it more convenient and simple compared to traditional methods.

For the HLS compatible version of video saving, you need to perform some initial setup steps mentioned in the extension's options. Once the initial setup is complete, you can use the basic video saving function by opening any video page (sm~) and right-clicking on the video screen to open the system message. After the automated process, a save dialog will open or the video will be downloaded to the default folder.

Please note that you should be aware of various legal regulations when using this extension. The processing in step 2 of the usage method depends on your network speed. Additionally, while this extension is enabled, the processing in step 2 will be automatically performed every time you open a NicoNico video page, resulting in data usage. Please be mindful of your data usage and other considerations.