The .gitignore Generator builds a .gitignore from compact built-in templates. Tick the languages, editors, and operating systems your project uses and it assembles one titled section per choice, removing any patterns that repeat between sections.
It runs in the page and remembers your selection in your own browser. Nothing is uploaded.
They cover the patterns that matter most for each ecosystem. Add anything project-specific by hand.
In the order you tick them.
Yes. If two sections both list, say, build/, it appears once.
No. The file is built entirely in your browser.