From what I can tell, this is a script to export manga titles from MangaDex. From the video in the post you linked you can see that it says it's an export for your library. Now I haven't used the script, but I did take a quick look at the code. The language for each entry uses your preferred language, but has a number of fallback languages in case your chosen language doesn't exist.
The reason I looked into the code, was because under normal circumstances, you can't just get user library data unless you use the API or are scraping the webpages. Scraping the webpages is never advised and against MangaDex's policies, but in order to use the API,
you'd normally need to register an API client on MangaDex's settings page and provide the script with your username, password, API client name and secret. Clearly you don't do that when using this script, so what's going on?
Basically you're doing a "manual XSS attack" on yourself so the script can hijack the session. You need to be logged into MangaDex first and when you run the script, it will grab the access token it needs to do the requests from your browser's localstorage:
https://github.com/rRoler/bookmarkl...6793c38c/src/websites/mangadex/website.ts#L72
This is a typical case of choosing user friendliness over security, where the user will have to really trust that the script they're running isn't malicious. For almost all cases, this is a major red flag and is an example of why you should never run scripts you don't trust, let alone don't understand. That said, just because you go through the hoops of providing all kinds of information to allow a script to access your account "the right way", doesn't take away you're allowing a script you don't understand to do what it promises to do. The moral of the story is to always be careful of 3rd party scripts.
Now to conform to the thread's format, here's a question:
If you're a mod/admin: does MangaDex allow such scripts to be used and advertised on the forums given how they handle authentication with the site?
If you're not a mod: would you choose run a 3rd party script like this, because it promises to do what you need it to and the site itself doesn't provide that feature, or would you rather be skeptical about running 3rd party scripts you don't understand to avoid bad things happening?