There is a TODO in frontend/@types/console/index.d.ts:

 
// TODO: Remove when upgrading to TypeScript 4.1.2+, which has a type for ListFormat and RelativeTimeFormat.
declare namespace Intl {
type ListFormatOptions = {
localeMatcher: string;
type: string;
style: string;
{color:#b5b3aa}};

class ListFormat {
constructor(locales?: Locale | string | undefined, options?: Partial<ListFormatOptions>);
public format(list?: Iterable<string>): string;
{color:#b5b3aa}}

class RelativeTimeFormat {
constructor(locale: string);
format(n: number, unit: string);
{color:#b5b3aa}}
}
 
We are currently using typescript 4.5.5 which is is newer than typescript 4.1.2, so this code is safe to remove