Correct, You have to import it. There was some discussion on adding the types to the library but that hasn’t happened yet so you’ll need to add to the top of your script.
var { PercentType } = require(@runtime);
which will import the full JSR223 presets into your script. However, that will override items which may break things (I can’t tell, screenshots are useless on the forum, in the future please post the text).
So you probably will need to do something like:
var runtime = require('@runtime');
new runtime.PercentType(50)
That’s because you assigned @runtime to a variable.
By default there is a bunch of stuff that gets imported from openhab-js (unless you turn that off). Some of that stuff uses the same name as the JSR223 default context which gets imported by @runtime. So if you just import all of @runtime to the current Object, items from runtime, which is a java.util.Map of Item names and their current state will override items from openhab-js which is a JavaScript Object which centralizes all your interactions with Items.