Quantifiers indicate numbers of characters or expressions to match. By default quantifiers like * and + are "greedy", meaning that they try to match as much of the string as possible. The ? character after the quantifier makes the quantifier "non-greedy": meaning that it will stop as soon as it finds a match.
"some <foo> <bar> new </bar> </foo> thing".match(/<.*>/) ➞ "<foo> <bar> new </bar> </foo>"
"some <foo> <bar> new </bar> </foo> thing".match(/<.*?>/) ➞ "<foo>"Find all HTML comments in the text. Use the ? in your expression.
let str = `... <!-- My -- comment test --> .. <!----> .. `;
str.match(regexp) ➞ "<!-- My -- comment test -->", "<!---->"Check the Resources if you get stuck.