The “!g” is part of something called “bangs” on DuckDuckGo. Bangs are prefixes to redirect your query to another search engine. For example “!g How to pet a cat” will redirect you to Google, searching for “How to pet a cat”

Other useful bangs are “!m” for maps, “!gi” for Google images, “!so” for stack overflow.

You can find more about it at the bangs page: https://duckduckgo.com/bangs

I think OP means seeding torrents, not serving media like Jellyfin does