How to use dev tools?

[hmaAst]

At the top of my screen it always says "dev tools active", but how do I actually use them?

[Alistair]

You can press 'O' (The letter O, not zero) to enable/disable dev tools.

Here is a list of things you can do with it active: https://rain-world-modding.fandom.com/wiki/Dev_Tools

[hmaAst]

Cool, thanks!