Struct ItemTooltipEvent 

pub struct ItemTooltipEvent<'a> {
    pub player: u128,
    pub player_entity_id: i32,
    pub stack: &'a ItemStack,
    pub display: &'a TooltipDisplay<'a>,
    pub advanced: bool,
    pub creative: bool,
    pub lines: &'a mut Vec<(Text, u32)>,
}

What Hooks::item_tooltip is told. Each field is that hook’s argument of the same name, described in the hook’s doc.

Fields

player: u128

player_entity_id: i32

stack: &'a ItemStack

display: &'a TooltipDisplay<'a>

advanced: bool

creative: bool

lines: &'a mut Vec<(Text, u32)>